EP3291922A1

EP3291922A1 - Method for producing a multilayered coating on plastic substrates

Info

Publication number: EP3291922A1
Application number: EP16719014.9A
Authority: EP
Inventors: Jürgen Bauer; Audree Andersen; Hardy Reuter; Roland Ratz; Sina Winnen; Marita BUERMANN; Vera DIEPENBROCK
Original assignee: BASF Coatings GmbH
Current assignee: BASF Coatings GmbH
Priority date: 2015-05-06
Filing date: 2016-03-31
Publication date: 2018-03-14
Also published as: WO2016177515A1; KR102059586B1; US10363572B2; BR112017023648B1; JP6689882B2; CA2982027C; RU2686904C1; US20180141084A1; JP2018521834A; MX2017014221A; KR20170133470A; CA2982027A1; CN107548322B; CN107548322A; BR112017023648A2

Abstract

The invention relates to a method for producing a multilayered coating on a plastic substrate, wherein a base coat layer, or a plurality of directly consecutive base coat layers are produced on a plastic substrate, a clear coat layer is produced directly on the one of the base coat layers, or on the upper-most of the plurality of base coat layers, and subsequently, the one base coat layer or the plurality of base coat layers and the clear coat layer are hardened together. The method is characterized in that at least one base coating material used for producing the base coat layers comprises at least one aqueous polyurethane-polyurea dispersion (PD) containing polyurethane-polyurea particles, wherein the polyurethane-polyurea particles contained in the dispersion (PD) contain anionic groups and/or groups that can be converted to anionic groups and have an average particle size of from 40 to 2000 nm and a gel content of at least 50%.

Description

Process for producing a multicoat paint system on plastic substrates

The present invention relates to a process for the production of a multicoat paint system on plastic substrates in which a basecoat film or several directly successive basecoat films are produced on a plastic substrate, a clearcoat film is prepared directly on one or the uppermost of the multiple basecoat films, and then the one or more basecoat films and the clearcoat layer cured together. In addition, the present invention relates to a multi-layer coating, which was prepared by the process according to the invention. The method can be used, for example, in the field of vehicle painting, for example in the painting of vehicle parts and accessories.

PRIOR ART Plastics have prevailed in the context of vehicle painting as materials for vehicle parts as well as vehicle mounting and accessory parts both indoors and outdoors. Plastics as well as other materials for decorative reasons (for example, coloring) and / or due to technical expediency (for example, light and weather resistance) coated with appropriate coating agents such as basecoats and clearcoats or painted. While the basecoat layer produced by the application of a corresponding basecoat material is primarily responsible for the production of aesthetic properties such as the color and / or effects such as the flop, the clearcoat film generally prepared on the basecoat film in particular serves the scratch resistance and the gloss of the then present multicoat paint system.

An important prerequisite for a high-quality coating is the adhesion to the substrate, that is to the substrate surface. It is generally known that especially in the coating or coating of plastics, in particular of non-polar plastics, such as polypropylene (PP) in pure form or in modified form (for example by adding ethylene-propylene-diene copolymers (EPDM)), sometimes serious adhesion problems can occur to the plastic substrate. In order to achieve acceptable adhesion of the particular coating agent, such non-polar plastics are conventionally subjected to a surface-activating pretreatment. The most commonly used methods are flaming, plasma treatment and corona discharge. It is also known to use certain fillers or adhesion primers, which among other things can contribute to improving the adhesion of a subsequent layer structure. Such fillers or adhesion primers are applied to the plastic substrate in a separate coating process, before the topcoat and clearcoat layer described above are then prepared thereon.

Even with surface-activating pretreatment and / or the production of filler or adhesive primer layers, the adhesion of coatings to plastic substrates is not always sufficient, so that they gradually detach from the substrate due to, for example, weathering or mechanical stress. When using aqueous coating compositions, which are becoming more and more prevalent in the plastic coating from an ecological point of view, the adhesion problems, especially in the coating of non-polar plastic substrates due to the polarity differences of the two media, the plastic substrate and the coating agent, are even more pronounced.

Accordingly, a relevant challenge for the automotive industry is to find methods by which multicoat paint systems can be produced by coordinating process parameters and employed coating materials which have outstanding adhesion to plastic substrates.

Object of the invention

It was therefore an object of the present invention to provide a process for producing a multicoat paint system on plastic substrates, in which the conventional structure of basecoat film and clearcoat film can be realized, but at the same time excellent adhesion of the multilayer structure to the substrate is guaranteed. This should be possible, although the basecoat should be prepared by the use of aqueous basecoats.

It has been found that the stated objects can be achieved by a special new method for producing a coating (M) on a plastic substrate (S), the method comprising the following steps:

(1) Preparation (1 .1) of a Basecoat Layer (B.1 .1) or (1 .2) of Several Directly Following Basecoat Films (B.1 .2.x) on the Plastic Substrate (S) by (1 .1) Applying an aqueous basecoat material (b.1 .1) to the substrate (S) or (1 .2) directly successively applying a plurality of basecoats (b.1 .2.x) to the substrate,

(2) Preparation of a clearcoat film (K) directly on (2.1) the basecoat film (B.1.1) or (2.2) of an uppermost basecoat film (B.1.2.x) by applying a clearcoat (k) directly to (2.1 ) the basecoat film (B.1.1) or (2.2) the topmost basecoat film (B.1.2.x),

(3) joint curing of the (3.1) basecoat film (B.1.1) and the clearcoat film (K) or (3.2) of the basecoat films (B.1.2.x) and the clearcoat film (K), characterized in that the Basecoat (b.1 .1) or at least one of the basecoats (b.1 .2.x) comprises at least one aqueous polyurethane-polyurea dispersion (PD) comprising polyurethane-polyurea particles, wherein the dispersion contained in the dispersion (PD) Polyurethane polyurea particles contain anionic and / or groups which can be converted into anionic groups and have an average particle size of 40 to 2000 nm and a gel content of at least 50%.

The abovementioned method is also referred to below as the method according to the invention and is accordingly the subject of the present invention. Preferred embodiments of the method according to the invention are given in the description below and in the subclaims. Furthermore, the present invention is a multi-layer coating on a plastic substrate, which was prepared by the method according to the invention.

The inventive method allows the production of multi-layer coatings on plastic substrates, which include the common structure of the basecoat film and clearcoat film and at the same time have excellent adhesion to the plastic substrate.

Detailed description

First, some terms used in the context of the present invention will be explained.

The application of a coating agent to a substrate or the production of a coating layer on a substrate are as follows. The respective coating agent is applied such that the coating layer produced therefrom is arranged on the substrate, but does not necessarily have to be in direct contact with the substrate. For example, other layers may be arranged between the coating layer and the substrate. For example, in step (1) of the method according to the invention, at least one basecoat film is produced on the plastic substrate (S), but at least one further coat, for example a filler or adhesive primer coat, can be arranged between the substrate and the basecoat film. The same principle applies to the application of a coating agent (b) to a coating layer (A) produced by means of another coating agent (a) (that is to say the production of a coating layer (B) on another coating layer (A)). The coating layer (B) does not necessarily have to be in contact with the coating layer (A), it merely has to be arranged above it, that is to say on the side of the coating layer (A) facing away from the substrate. By contrast, applying a coating agent directly to a substrate or producing a coating layer directly on a substrate is understood as follows. The respective coating agent is applied such that the coating layer produced therefrom is arranged on the substrate and is in direct contact with the substrate. In particular, no other layer is arranged between the coating layer and the substrate.

The same naturally applies to the application of a coating composition (b) directly to a coating layer (A) produced by means of another coating agent (a) (ie the preparation of a coating layer (B) directly on another coating layer (A)). In this case, the two coating layers are in direct contact, so they are arranged directly on top of each other. In particular, there is no further layer between the coating layers (A) and (B). Of course, the same principle applies to a direct sequential application of coating compositions or the production of directly successive coating layers.

In the context of the present invention, flash drying, intermediate drying and hardening are to be understood as meaning the term contents familiar to the person skilled in the art in connection with processes for producing multicoat paint systems.

Thus, the term bleeding is basically understood to mean the evaporation or evaporation of organic solvents and / or water of a coating agent applied during the production of a coating at usually ambient temperature (ie room temperature), for example 15 to 35 ° C. for a period of for example, 0.5 to 30 minutes. During the flash-off, organic solvents and / or water which are contained in the applied coating agent evaporate. In any case, since the coating material is still flowable directly after application and at the beginning of venting, it can run during the venting process. Because at least one applied by spray application coating agent is usually applied droplet-shaped and not in a homogeneous thickness. But it is flowable by the contained organic solvents and / or water and can thus by the Smoothing form a homogeneous, smooth coating film. At the same time, organic solvents and / or water evaporate successively, so that after the ablation phase, a comparatively smooth coating layer has formed, which contains less water and / or solvent compared to the applied coating composition. However, the coating layer is not yet ready for use after it has been flashed off. It is, for example, no longer flowable, but still soft or sticky, possibly only dried. In particular, the coating layer is not yet cured as described below.

Intermediate drying is therefore also understood to mean the evaporation or evaporation of organic solvents and / or water of a coating agent applied during the production of a coating, usually at a temperature of, for example, 40 to 90 ° C., higher than the ambient temperature, for a duration of, for example, 1 to 20 min. Even with intermediate drying, the applied coating agent will thus lose a proportion of organic solvents and / or water. With respect to a particular coating agent is generally considered that the intermediate drying in comparison to bleeding at, for example, higher temperatures and / or for a longer period of time is done, so compared to bleeding and a higher proportion of organic solvents and / or water from the escaped coating layer escapes. But even the intermediate drying gives no coating layer ready for use, that is no hardened as described below coating layer. For example, a typical sequence of flash and intermediate drying would be to flash off an applied coating layer for 10 minutes at ambient temperature and then to dry at 80 ° C for 10 minutes. However, a final distinction between the two terms is neither necessary nor wanted. For the sake of clarity, these terms are used to make it clear that one of the curing described below can be preceded, variable and sequential conditioning a coating layer. In this case, depending on the coating agent, the evaporation temperature and evaporation time, more or less high proportions of the organic solvent contained in the coating agent and / or water evaporate. If necessary, even a proportion of those in the Coating polymers contained as binder as described below together or looped. However, both during the drying and during the intermediate drying, no ready-to-use coating layer is obtained, as is the case with the curing described below. As a result, curing is clearly differentiated from flash off and intermediate drying.

Accordingly, hardening of a coating layer is understood to mean the transfer of such a layer into the ready-to-use state, that is to say into a state in which the substrate equipped with the respective coating layer can be transported, stored and used as intended. A cured coating layer is thus no longer particularly soft or sticky, but conditioned as a solid coating film, which no longer substantially changes its properties such as hardness or adhesion to the substrate even upon further exposure to curing conditions as described below. As is known, coating compositions can basically be cured physically and / or chemically, depending on the constituents contained, such as binders and crosslinking agents. In the case of chemical curing, in particular the thermal-chemical curing is considered. A coating composition may, for example if it is thermally-chemically curable, be self-crosslinking and / or externally-crosslinking. By specifying that a coating agent is self-crosslinking and / or externally crosslinking, it is to be understood in the context of the present invention that this coating composition contains polymers as binders and optionally crosslinking agents which can crosslink together accordingly. The underlying mechanisms as well as usable binders and crosslinking agents are described below.

In the context of the present invention, "physically curable" or the term "physical curing" means the formation of a cured coating layer by release of solvent from polymer solutions or polymer dispersions, the curing being achieved by entanglement of polymer chains. Such coating compositions are usually formulated as one-component coating compositions. In the context of the present invention, "thermally-chemically curable" or the term "thermal-chemical curing" means the crosslinking of a lacquer layer initiated by chemical reaction of reactive functional groups (formation of a hardened coating layer), the energetic activation of this chemical reaction by thermal energy is possible. In this case, different functional groups which are complementary to one another can react with one another (complementary functional groups) and / or the formation of the hardened layer is based on the reaction of autoreactive groups, that is to say functional groups which react with each other with groups of their type. Examples of suitable complementary reactive functional groups and autoreactive functional groups are known, for example, from German Patent Application DE 199 30 665 A1, page 7, line 28, to page 9, line 24.

This crosslinking can be a self-crosslinking and / or an external crosslinking. If, for example, the complementary reactive functional groups are already present in an organic polymer used as a binder, for example a polyester, a polyurethane or a poly (meth) acrylate, self-crosslinking is present. Crosslinking is present, for example, when a (first) organic polymer containing certain functional groups, for example hydroxyl groups, reacts with a crosslinking agent known per se, for example a polyisocyanate and / or a melamine resin. The crosslinking agent thus contains reactive functional groups which are complementary to the reactive functional groups present in the (first) organic polymer used as binder. In particular, in the case of external crosslinking are the per se known one-component and multi-component systems, in particular two-component systems into consideration.

In thermally-chemically curable one-component systems, the components to be crosslinked, for example organic polymers as binders and crosslinking agents, are present next to one another, that is to say in one component. requirement This is because the components to be crosslinked only react with one another at elevated temperatures of, for example, above 100 ° C., that is, undergo curing reactions. Otherwise, the components to be crosslinked would have to be stored separately from one another and mixed with one another shortly before application to a substrate, in order to avoid premature, at least proportional, thermochemical curing (compare two-component systems). As an example of a combination, hydroxy-functional polyesters and / or polyurethanes with melamine resins and / or blocked polyisocyanates may be mentioned as crosslinking agents.

In thermally-chemically curable two-component systems, the components to be crosslinked, for example the organic polymers as binders and the crosslinking agents, are present separately from one another in at least two components which are combined only shortly before application. This shape is chosen when the components to be cross-linked already react at ambient temperatures or slightly elevated temperatures between 40 and 100 ° C. As an example of a combination, hydroxy-functional polyesters and / or polyurethanes and / or poly (meth) acrylates with free polyisocyanates as crosslinking agents may be mentioned.

It is also possible that an organic polymer has as binder both self-crosslinking and externally crosslinking functional groups and then combined with crosslinking agents.

Of course, in the curing of a thermally-chemically curable coating agent is always a physical cure, that is a entanglement of polymer chains occur. Nevertheless, such a coating composition is then referred to as thermally-chemically curable.

It follows from the above that, depending on the nature of the coating composition and the components contained therein, curing is effected by different mechanisms, which of course also make different conditions necessary during the curing, in particular different curing temperatures and curing times. In the case of a purely physically curable coating agent, curing preferably takes place between 15 and 100 ° C., preferably between 40 and 100 ° C., over a period of, for example, 5 minutes to 48 hours, preferably 10 to 60 minutes. In this case, the curing of flash-off and / or intermediate drying thus differs possibly only by the duration of the conditioning of the coating layer.

In the case of thermo-chemically curable coating compositions, the following applies. The thermal-chemical curing of thermally-chemically curable one-component systems is carried out, for example, at temperatures of 100 to 200 ° C, preferably 120 to 200 ° C for a period of 10 to 60 minutes, preferably 15 to 50 minutes, since these conditions are usually necessary to convert the coating layer by chemical crosslinking reactions in a thermo-chemically cured coating layer. Accordingly, a flash-off and / or intermediate drying phase taking place before the thermochemical curing takes place at lower temperatures and / or for shorter times.

The thermal-chemical curing of thermally-chemically curable two-component systems is carried out at temperatures of, for example, between 15 and 100 ° C., preferably between 40 and 100 ° C., for a period of 5 to 80 minutes, preferably 10 to 60 minutes. Once again, a flash and / or intermediate drying phase taking place before the thermochemical curing takes place at lower temperatures and / or for shorter times.

Equally possible is that a basically thermally-chemically curable coating agent is only physically cured. Thus, a thermo-chemically curable one-component coating composition, which contains, for example, a combination of hydroxy-functional binders and typical amino resins and only at temperatures of, for example, above 100 ° C chemically cures, are cured physically at only 80 ° C. The possibly taking place in very minor proportion chemical crosslinking is then negligible. By combining appropriate polymeric binders and Aminoplast resins, which are then purely physically cured in the cured coating, for example, certain property profiles can be achieved.

Since this is ultimately a purely physical hardening, in this case, the curing of flash-off and / or intermediate drying thus optionally also differs only by the duration of the conditioning of the coating layer.

The following is also possible. If, for example, a basically thermally-chemically curable one-component basecoat material is selected in the context of the process according to the invention and if it is used to prepare a basecoat film or topmost basecoat film, a clearcoat is applied directly to this film. Finally, both layers are cured together. If the clear coat is a thermally-chemically curable two-component coating agent, which is preferred, then the final curing may be carried out at, for example, 80 ° C. The clearcoat is cured thermally-chemically, while the components contained in the applied basecoat can only cure physically at this temperature.

All temperatures explained in the context of the present invention are understood to mean the temperature of the room in which the coated substrate is located. What is meant is not that the substrate itself must have the appropriate temperature.

Of course, depending on the plastic substrate used, care must be taken during the process according to the invention that the substrate is not heated to such an extent during the curing of paint layers applied thereon that it decomposes or deforms. However, common plastic substrates, especially those used in vehicle painting, are generally not dimensionally stable at temperatures of 100.degree. C. and higher. Accordingly, the curing of coating layers in the present invention is preferably carried out at below 100 ° C. From what has been said above, it thus follows that in the context of the present invention, the following hardening processes are preferably realized. Physically cured coating compositions and thermally-chemically curable single-component cross-linking coating agents are physically cured; thermally-chemically curable, externally crosslinking two-component coating compositions are thermally-chemically cured. This ensures that the substrate only has to be heated to temperatures of less than 100 ° C. It is therefore preferred that any curing processes in the context of the process according to the invention are carried out at below 100 ° C., more preferably at not more than 90 ° C. If reference is made in the context of the present invention to an official standard without reference to the official period of validity, this naturally includes the version of the standard applicable at the filing date or, if no valid version at that time, the last valid version. The method according to the invention

In the context of the method according to the invention, a multicoat system is built up on a plastic substrate (S). Suitable plastic substrates (S) are conventional plastics, for example polystyrene (PS), polyvinyl chloride (PVC), polyurethane (PUR), glass fiber-reinforced unsaturated polyesters, polymethyl methacrylate (PMMA), polyphenylene sulfide (PPS), polyoxymethylene (POM), polyphenylene ether (PPE) , Polyphenylene oxide (PPO), polyurea, polybutadiene terephthalate (PBT), polycarbonate (PC), acrylonitrile-butadiene-styrene copolymers (ABS) and polyolefins such as polypropylene (PP). Also possible are plastic substrates containing various of the plastics mentioned, therefore mixtures of these plastics. By way of example, reference is made to polypropylene (PP) modified with ethylene-propylene-diene copolymers (EPDM), (PP / EPDM blends). Preference is given to PP / EPDM blends with EPDM contents of, for example, not higher than 25% by weight, in particular not higher than 20% by weight. The plastic substrates may be simple plastic plates. Are possible as substrates but also vehicle bodies made of plastics or certain vehicle parts and Fahrzeuganbau- and accessories for both the vehicle interior and the vehicle exterior. The substrates can be pretreated in a manner known per se. In particular, surface-activating pretreatments such as flaming, plasma treatment and corona discharge, in particular flaming, are suitable.

As an alternative or in addition to the described surface-activating pretreatment, the substrates can be provided with basically known filler coatings or adhesive primer coatings. Corresponding coating compositions are known and can be applied, for example, directly to the optionally surface-activating pretreated substrate and then cured. However, it is of very particular advantage that can be completely dispensed with the use of a filler or adhesive primer in the context of the inventive method, but nevertheless excellent adhesion properties result.

In step (1) of the process according to the invention, (1 .1) a basecoat film (B.1 .1) is prepared or (1 .2) a plurality of directly successive basecoat films (B.1 .2.x) are prepared. The layers are produced by applying (1 .1) an aqueous basecoat (b.1 .1) to the plastic substrate (S) or (1 .2) directly successively applying several basecoats (b.1 .2.x) on the plastic substrate (S).

The basecoats can be applied directly to the substrate, ie between the optionally surface-activating pretreated substrate and the basecoat (b.1 .1) or the first (that is to say the lowest) of the basecoats (b.1 .2.x) are no further Layers arranged. However, it is equally possible for at least one other coating layer, such as a filler layer, to be produced on the substrate first. But since, despite the abandonment of such other coating layers an excellent Adhesion is achieved and this waiver leads to an enormous simplification of the process, preferably the basecoat (b.1 .1) or the first basecoat (b.1 .2.x) is applied directly to the optionally surface-activating pretreated plastic substrate.

The direct successive application of several basecoats (b.1 .2.x) to the substrate (S) is thus understood to mean that first a first basecoat is applied to the substrate and then a second basecoat is applied directly to the layer of the first basecoat is applied. An optionally third basecoat is then applied directly to the layer of the second basecoat. This process can then be repeated analogously for further basecoats (ie a fourth, fifth, etc. basecoat).

The terms basecoat material and basecoat film in relation to the coating agents and coating layers applied in step (1) of the process according to the invention are used for the sake of clarity. A basecoat is to be understood as meaning a coloring intermediate coating substance used in the automotive finishing and general industrial coating. In order to protect a basecoat film, in particular against environmental influences, at least one additional clearcoat film is generally applied to this coat as well as within the scope of the inventive process. The curing then takes place together with the clearcoat.

The basecoats (b.1.1) and (b.1.2.x) are described in detail below. However, these are preferably physically curable basecoats and / or thermochemically curable externally crosslinking one-component basecoats. The basecoat (b.1.1) and the basecoat materials (b.1.2.x) can be applied by the methods known to those skilled in the art for the application of liquid coating compositions, for example by dipping, knife coating, spraying, rolling or the like. Preferably, spray application methods are used, such as compressed air spraying (pneumatic application), airless spraying, high rotation, electrostatic spray application (ESTA), optionally combined with hot spray application such as hot air (hot spraying). Most notably Preferably, the basecoats are applied via the pneumatic spray application or the electrostatic spray application.

The application of the basecoat (b.1 .1) thus produces a basecoat film (B.1 .1), that is to say a layer of the basecoat (b.1 .1) applied to the plastic substrate (S).

Within the scope of stage (1 .2) of the process according to the invention, the following name is suitable. The basecoats and basecoats are generally characterized by (b.1.2.x) and (B.1.2.x), while in naming the specific individual basecoats and basecoats, the x can be replaced by correspondingly appropriate other letters.

The first basecoat and the first basecoat film can be labeled a, the topmost basecoat and the topmost basecoat film can be labeled z. These two basecoats or basecoats are present in the stage (1 .2) in any case. Optionally interposed layers may be consecutively labeled b, c, d and so on.

By applying the first basecoat (b.1 .2.a), a basecoat film (B.1 .2.a) is thus produced on the plastic substrate (S). The at least one further basecoat film (B.1 .2.x) is then produced directly on the basecoat film (B.1 .2.a). If several further basecoat films (B.1 .2.x) are produced, these are prepared directly in succession. The basecoats (b.1 .2.x) can be identical or different. It is also possible to produce several basecoat films (B.1.2.x) with the same basecoat and one or more further basecoat films (B.1.2.x) with one or more other basecoats. If a first basecoat film is prepared by applying a first basecoat material and a second basecoat film is applied by applying the same basecoat material, then obviously both layers on the same basecoat. However, the application is obviously carried out in two stages, so that the corresponding basecoat in the sense of the inventive method corresponds to a first basecoat (b.1 .2.a) and another basecoat (b.1 .2.z). The described construction is often also referred to as a single-layer basecoat layer structure produced in two jobs. Since, however, due to the technical conditions in a paint shop between the first job and the second job, a certain period of time always elapses, during which the substrate, for example the automobile body, is conditioned at, for example, 15 to 35 ° C. and thus vented, the characterization of this structure as a two-layer basecoat construction is formally more distinct. The described process control is thus assigned to the second variant of the method according to the invention.

In step (1 .1), the applied basecoat (b.1 .1) or the corresponding basecoat film (B.1 .1) after application, for example, at 15 to 35 ° C for a period of, for example, 0.5 to 30 min vented and / or intermittently dried at a temperature of preferably 40 to 90 ° C for a period of, for example, 1 to 20 minutes. Preferably, the mixture is first flashed off at 15 to 35 ° C. for a period of 0.5 to 30 minutes and then intermediately dried at 40 to 90 ° C. for a period of, for example, 1 to 20 minutes.

In step (1 .2), the applied basecoats (b.1 .2.x) are generally flashed off on their own and / or with one another and / or inter-dried. Preference is also in the context of stage (1 .2) at 15 to 35 ° C for a period of 0.5 to 30 minutes and flashed at 40 to 90 ° C for a period of, for example, 1 to 20 minutes between dried. The sequence of venting and / or intermediate drying of one or more base coat layers (B.1 .2.x) can be adapted to the requirements of the individual case.

The basecoat film (B.1.1) or basecoat films (B.1.2.x) are not cured within stage (1) of the process of the invention. This results clearly and directly from the below described step (3) of the method according to the invention. Since the basecoat films are cured only in step (3), they can not already hardened in the stage (1), because then the hardening in stage would no longer be possible.

The basecoat films are therefore not exposed in step (1) conditions that may already lead to a cure. These conditions are of course dependent on the basecoats used in each case. In any case, this means in any case that the basecoat films are preferably exposed only to temperatures of less than 100 ° C. It is again preferred that they are only exposed to temperatures of less than 100 ° C and additionally exposed to temperatures between 60 and 100 ° C for no longer than 15 minutes. Because under these conditions, the preferred basecoats, that is, physically curable basecoats and / or thermo-chemically curable externally crosslinking one-component basecoats, are generally not cured. Because of the given temperatures in question physical curing is usually not complete within the specified times.

The application of the basecoats (b.1 .1) and (b.1 .2.x) takes place in such a way that the basecoat film (B.1.1) and the individual basecoat films (B.1.2.x) are applied according to the method described in US Pat Stage (3) curing have a layer thickness of, for example, 3 to 50 microns, preferably 5 to 40 microns.

In step (2) of the process according to the invention, a clearcoat film (K) is produced directly on (2.1) the basecoat film (B.1 .1) or (2.2) of the topmost basecoat film (B.1 .2.z). This preparation is carried out by appropriate application of a clearcoat (k). The clearcoat layer (K) is therefore arranged directly on the basecoat film (B.1 .1) or directly on the topmost basecoat film (B.1 .2.z).

The clearcoat (k) may be a transparent coating agent known per se to the person skilled in the art in this sense. Under transparent is to be understood that a layer formed with the coating agent is not color-covering, but is constituted so that the color of the underlying base paint assembly is visible. As you know, this does not exclude that Clearcoat in minor amounts may also contain pigments which may, for example, support the color depth of the overall structure.

These are aqueous or solvent-containing transparent, physically curing or thermally-chemically curable coating compositions, the latter being able to be formulated both as a one-component and as a two- or multi-component coating composition. Also suitable are powder slurry clearcoats. Preference is given to solvent-based clearcoats.

The clearcoats (k) used can in particular be thermally-chemically and / or chemically-actinically curable. In particular, they are thermally-chemically curable and externally crosslinking. Preference is given to thermally-chemically curable two-component clearcoats.

The clearcoats therefore usually and preferably contain at least one (first) polymer as binder with functional groups and at least one crosslinker with a functionality complementary to the functional groups of the binder. At least one hydroxy-functional poly (meth) acrylate polymer is preferably used as the binder and a free polyisocyanate as the crosslinking agent. The clearcoat (k) is applied by the methods known to those skilled in the application of liquid coating compositions, for example by dipping, knife coating, spraying, rolling or the like. Preferably, spray application methods are used, such as compressed air spraying (pneumatic application), and electrostatic spray application (ESTA).

The clearcoat (k) or the corresponding clearcoat film (K) is preferably flashed after the application at 15 to 35 ° C for a period of 0.5 to 30 minutes or intermediate dried. Such flash-off or intermediate drying conditions apply in particular to the preferred case that the clearcoat (k) is a thermally-chemically curable two-component coating composition. However, this does not rule out that the clearcoat (k) on other curable coating agent and / or other flash or intermediate drying conditions are used.

The application of the clearcoat material (k) takes place in such a way that the clearcoat film has, after curing in step (3), a layer thickness of, for example, 15 to 80 micrometers, preferably 20 to 65 micrometers, particularly preferably 25 to 60 micrometers.

Of course, within the scope of the process according to the invention, it is not excluded that after the application of the clearcoat (k) further coating agents, for example further clearcoats, are applied and in this way further coating layers, for example further clearcoat films, are produced. Such further coating layers are then also cured in step (3) described below, or they are applied after step (3) and then cured separately. However, preferably only one clearcoat (k) is applied and then cured as described in step (3).

In step (3) of the process according to the invention, a joint curing of the (3.1) basecoat film (B.1 .1) and the clearcoat film (K) or (3.2) of the basecoat films (B.1 .2.x) and the clearcoat film (K. ). The curing conditions, of course, depend on the basecoats and clearcoats used, if appropriate also on the conditions in which the basecoat film (B.1.1) or the basecoat films (B.1.2.x) were flashed off and temporarily dried. The joint curing is preferably carried out at temperatures between 40 and 100 ° C, more preferably between 60 and 100 ° C, for a period of, for example, 5 to 60 minutes, preferably 20 to 60 minutes. In this way, on the one hand, in any case, the preferably used thermally-chemically curable two-component clearcoats can be thermally-chemically cured. On the other hand, the basecoats which are preferably used, that is to say physically curable basecoats and / or thermo-chemically curable externally crosslinking one-component basecoats, are in any case physically hardened. At the same time it is avoided that the plastic substrates can decompose or deform. If, for example, an applied basecoat requires a significantly longer duration for physical curing, it is of course also possible to harden longer in the final curing process and / or flash off or intermediate drying in stage (1) of the process is carried out at the necessary temperatures, for example for a longer period of time.

After completion of stage (3) of the process according to the invention, a multicoat system according to the invention results. The basecoat materials to be used according to the invention

The basecoat (b.1 .1) to be used according to the invention comprises at least one, preferably exactly one, specific aqueous polyurethane-polyurea dispersion (PD). The polymer particles present in the dispersion are therefore polyurethane-polyurea-based. Such polymers can in principle be prepared by conventional polyaddition of, for example, polyisocyanates with polyols and polyamines. With regard to the dispersion (PD) to be used according to the invention or the polymer particles contained in it, however, special conditions explained below are to be observed.

The polyurethane-polyurea particles contained in the aqueous polyurethane-polyurea dispersion (PD) have a gel content of at least 50% (measuring method see example part). In addition, the polyurethane-polyurea particles contained in the dispersion (PD) have an average particle size (also called average particle size) of from 40 to 2,000 nanometers (nm) (for the method of measurement, see the example section).

The dispersions (PD) according to the invention are thus microgel dispersions. Because a microgel dispersion is known to be a polymer dispersion, in which on the one hand, the polymer in the form of relatively small On the other hand, the polymer particles are at least partially intramolecularly crosslinked, the latter meaning that the polymer structures present within a particle have a typical macroscopic network with three-dimensional Macroscopically, however, such a microgel dispersion is still a dispersion of polymer particles in a dispersion medium, for example water, although the particles may also have partial cross-linking bridges (this can scarcely be ruled out purely for reasons of production), however In any case, if the system is a dispersion containing discrete particles with a measurable mean particle size, but due to their molecular nature, they are dissolved in suitable organic solvents, whereas macroscopic networks would only be swollen.

Thus, since the microgels represent structures that are between branched and macroscopically crosslinked systems, thus combining the characteristics of suitable organic solvent-soluble macromolecules with network structure and insoluble macroscopic networks, the proportion of crosslinked polymers may not change until after isolation of the solid polymer Water and optionally organic solvents and subsequent extraction can be determined. It makes use of the fact that the originally soluble in suitable organic solvents microgel particles retain their internal network structure after isolation and behave in the solid as a macroscopic network. The crosslinking can be checked via the experimentally accessible gel fraction. Ultimately, the gel fraction is the fraction of the polymer from the dispersion which, as an isolated solid, can not be dissolved in a solvent in a molecularly disperse manner. It must be ruled out that subsequent crosslinking reactions in the isolation of the polymeric solid further increase the gel fraction. This insoluble fraction in turn corresponds to the proportion of the polymer present in the dispersion in the form of intramolecularly crosslinked particles or particle fractions. In the context of the present invention, it has been found that only microgel dispersions with polymer particles having particle sizes in the range essential to the invention all have the required performance properties. Thus, it is particularly important to combine rather small particle sizes with a significant amount of cross-linked content or gel content that nevertheless exists. Only in this way are the advantageous properties, in particular the combination of good optical and mechanical properties of multi-layer coatings on the one hand and a high solids and a good storage stability of aqueous basecoats on the other hand to achieve. For example, dispersions having comparatively larger particles in the range of, for example, greater than 2 micrometers (average particle size) have an increased settling behavior and thus a poorer storage stability.

The polyurethane-polyurea particles contained in the aqueous polyurethane-polyurea dispersion (PD) preferably have a gel content of at least 60%, more preferably of at least 70%, particularly preferably of at least 80%. The gel fraction can thus be up to 100% or approximately 100%, for example 99% or 98%. In such a case, therefore, all or approximately the entire polyurethane-polyurea polymer is present in the form of crosslinked particles.

The polyurethane-polyurea particles contained in the dispersion (PD) preferably have an average particle size of from 40 to 1500 nm, more preferably from 100 to 1000 nm, including preferably from 10 to 500 nm and more preferably from 120 to 300 nm preferred range is from 130 to 250 nm.

The resulting polyurethane-polyurea dispersion (PD) is aqueous. The term "aqueous" is known to the person skilled in the art in this context, which basically refers to a system which does not contain exclusively or mainly organic solvents (also called solvent) as the dispersion medium, but on the contrary contains a significant proportion of water as the dispersion medium aqueous character, based on the Maximum content of organic solvents and / or defined by the content of water are described below.

The polyurethane-polyurea particles contain anionic and / or anionic groups (that is, groups which can be converted to anionic groups by the use of known neutralizing agents, also mentioned below, such as bases).

As one skilled in the art knows, these are, for example, carboxylic acid, sulfonic acid and / or phosphonic acid groups, particularly preferably carboxylic acid groups (functional groups which can be converted into anionic groups by neutralizing agents) and anionic groups derived from the abovementioned functional groups, in particular carboxylate , Sulfonate and / or phosphonate groups, preferably carboxylate groups. The introduction of such groups is known to increase water dispersibility. Depending on the conditions chosen, the groups mentioned may be present proportionally or almost completely in one form (for example carboxylic acid) or in another form (carboxylate). A determining influencing factor is, for example, the use of the already mentioned neutralizers, which are described in more detail below. Regardless of the form in which the groups mentioned are present, in the context of the present invention, for the sake of clarity, a uniform designation is frequently chosen. If, for example, a specific acid number is specified for a polymer or a polymer is termed carboxy-functional, both the carboxylic acid groups and the carboxylate groups are always included here. If differentiation is to take place in this regard, this is done, for example, on the basis of the degree of neutralization.

The introduction of said groups into polymers such as, for example, the polyurethane-polyurea particles can be known to take place via the use of appropriate starting compounds in the preparation of the polymers. The starting compounds then contain the corresponding groups, for example carboxylic acid groups, and are replaced by further functional groups, for example Hydroxyl groups, polymerized in the polymer. Further details are described below.

Preferred anionic and / or anionic groups are carboxylate or carboxylic acid groups. The present in the dispersion in the form of particles polyurethane-polyurea polymer, based on the solids, preferably an acid number of 10 to 35 mg KOH / g, in particular from 15 to 23 mg KOH / g (measuring method see Example).

The polyurethane-polyurea particles contained in the dispersion (PD) preferably contain, in each case in reacted form, (Z.1 .1) at least one polyurethane prepolymer containing isocyanate groups, containing anionic groups and / or groups which can be converted into anionic groups, and 1 .2) at least one polyamine containing two primary amino groups and one or two secondary amino groups.

If it is stated in the context of the present invention that polymers, for example the polyurethane-polyurea particles of the dispersion (PD), contain certain components in reacted form, this is to be understood as meaning that these particular components are used as starting compounds in the preparation of the respective polymers become. Depending on the nature of the starting compounds, the respective conversion to the target polymer takes place according to different mechanisms. Thus, in the production of polyurethane-polyurea particles or polyurethane-polyurea polymers, the components (Z.1 .1) and (Z.1.2) become apparent by reaction of the isocyanate groups of (Z.1.1) with the amino groups of (Z.1 .2) with formation of urea bonds reacted together. The polymer then of course contains the pre-existing amino groups and isocyanate groups in the form of urea groups, that is, in their correspondingly reacted form. Nevertheless, the polymer ultimately contains the two components (Z.1 .1) and (Z.1 .2), because apart from the reacted isocyanate groups and amino groups, the components remain unchanged. Accordingly, for the sake of clarity, it is stated that the respective polymer contains the components, each in reacted form. The meaning of the expression "the polymer contains, in converted form, a component (X)" is thus to be equated with the meaning of the expression "in the preparation of the polymer, the component (X) was used".

It follows from the above that anionic groups and / or groups which can be converted into anionic groups are preferably introduced into the polyurethane-polyurea particles via the abovementioned isocyanate-group-containing polyurethane prepolymer.

Preferably, the polyurethane-polyurea particles of the two components (Z.1 .1) and (Z.1 .2), that is, they are prepared from these two components. The aqueous dispersion (PD) can be obtained by a specific three-step process, which is preferable. In the context of the description of this method, preferred embodiments of the components (Z.1 .1) and (Z.1 .2) are mentioned.

The method comprises

(I)

Preparation of a composition (Z) containing, in each case based on the total amount of the composition (Z),

(Z.1) 15 to 65 wt .-% of at least one isocyanate-containing intermediate with masked primary amino groups, the preparation of the reaction

(Z.1 .1) of at least one isocyanate group-containing polyurethane prepolymer containing anionic groups and / or groups which can be converted into anionic groups

(Z.1.2a) at least one polyamine containing two masked primary amino groups and one or two free secondary amino groups

by addition reaction of isocyanate groups (Z.1.1) with free secondary amino groups from (Z.1.2),

(Z.2) from 35 to 85% by weight of at least one organic solvent which, at a temperature of 20 ° C., has a solubility in water of not more than 38% by weight, (II)

Dispersion of the composition (Z) in the aqueous phase and

(III)

at least partial removal of the at least one organic solvent (Z.2) from the dispersion obtained under (II).

In the first step (I) of this process, therefore, a special composition (Z) is produced. The composition (Z) contains at least one, preferably exactly one specific isocyanate group-containing intermediate (Z.1) with masked primary amino groups.

The preparation of the intermediate (Z.1) comprises the reaction of at least one isocyanate group-containing polyurethane prepolymer (Z.1.1) containing anionic groups and / or groups which can be converted into anionic groups with at least one of a polyamine (Z.1.2) derived polyamine (Z.1.2a) containing at least two masked primary amino groups and at least one free secondary amino group.

Isocyanate group-containing polyurethane polymers containing anionic and / or groups which can be converted into anionic groups are known in principle. In the context of the present invention, the component (Z.1 .1) is referred to as a prepolymer for the sake of clarity. It is a polymer to be referred to as a precursor, since it is used as starting component for the preparation of another component, namely the intermediate (Z.1).

For the preparation of isocyanate group-containing polyurethane prepolymers (Z.1 .1) containing anionic and / or anionic groups can be converted groups known in the art aliphatic, cycloaliphatic, aliphatic-cycloaliphatic, aromatic, aliphatic-aromatic and / or cycloaliphatic aromatic polyisocyanates are used. Preference is given to using diisocyanates. By way of example, the following diisocyanates may be mentioned: 1, 3 or 1, 4 Phenylene diisocyanate, 2,4- or 2,6-toluene diisocyanate, 4,4'- or 2,4'-diphenylmethane diisocyanate, 1, 4- or 1, 5-naphthylene diisocyanate,

Diisocyanatodiphenyl ether, trimethylene diisocyanate, tetramethylene diisocyanate, ethylethylene diisocyanate, 2,3-dimethylethylene diisocyanate, 1-methyltrimethylene diisocyanate, pentamethylene diisocyanate, 1,3-cyclopentylene diisocyanate,

Hexamethylene diisocyanate, cyclohexylene diisocyanate, 1,2-cyclohexylene diisocyanate, octamethylene diisocyanate, trimethylhexane diisocyanate, tetramethylhexane diisocyanate, decamethylene diisocyanate, dodecamethylene diisocyanate, tetradecamethylene diisocyanate, isophorone diisocyanate (IPDI), 2-isocyanato-propylcyclohexyl isocyanate,

Dicyclohexylmethane-2,4'-diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, 1,4- or 1,3-bis (isocyanatomethyl) cyclohexane, 1,4-, or 1,3- or 1,2-diisocyanatocyclohexane, 2 , 4- or 2,6-diisocyanato-1-methylcyclohexane, 1-isocyanatomrthyl-5-isocyanato-1,3,3-trimethylcyclohexane, 2,3-bis (8-isocyanatooctyl) -4-octyl-5-hexylcyclohexene, tetramethylxylylene diisocyanates (TMXDI) such as m-tetramethylxylylene diisocyanate or mixtures of these polyisocyanates. The use of different dimers and trimers of said diisocyanates such as uretdiones and isocyanurates is of course possible. It is also possible to use polyisocyanates of higher isocyanate functionality. Examples of these are tris (4-isocyanatophenyl) methane, 1, 3,4-triisocyanatobenzene, 2,4,6-triisocyanatotoluene, 1,3,5-tris (6-isocyanatohexylbiuret), bis (2,5-diisocyanato-4 - methylphenyl) methane. Optionally, the functionality can be reduced by reaction with monoalcohols or secondary amines. However, preference is given to the use of diisocyanates, particularly preferably the use of aliphatic diisocyanates, such as hexamethylene diisocyanate, isophorone diisocyanate (IPDI), dicyclohexylmethane-4,4'-diisocyanate, 2,4- or 2,6-diisocyanato-1-methylcyclohexane, m- Tetramethylxylylene diisocyanate (m-TMXDI). An aliphatic is an isocyanate when the Isocyantgruppen are attached to aliphatic groups, that is in the alpha position to an isocyanate group no aromatic carbon is present.

To prepare the prepolymers (Z.1 .1), the polyisocyanates are generally reacted to form urethanes with polyols, especially diols. Examples of suitable polyols are saturated or olefinically unsaturated polyester polyols and / or polyether polyols. In particular, as polyols polyester polyols, in particular those having a number average molecular weight of 400 to 5000 g / mol (method of measurement see example), are used. Such polyester polyols, preferably polyester diols, can be prepared in known manner by reaction of corresponding polycarboxylic acids, preferably dicarboxylic acids, and / or their anhydrides with corresponding polyols, preferably diols, by esterification. Of course, if appropriate, monocarboxylic acids and / or monoalcohols may also be used proportionately for the preparation. The polyester diols are preferably saturated, in particular saturated and linear.

Examples of suitable aromatic polycarboxylic acids for the preparation of such polyester polyols, preferably polyester diols, are phthalic acid, isophthalic acid and terephthalic acid, of which isophthalic acid is advantageous and is therefore preferably used. Examples of suitable aliphatic polycarboxylic acids are oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedicarboxylic acid and dodecanedicarboxylic acid or else hexahydrophthalic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 4-methylhexahydrophthalic acid, tricyclodecanedicarboxylic acid as well as tetrahydrophthalic acid. Dicarboxylic acids which can also be used are dimer fatty acids or dimerized fatty acids, which are known to be mixtures which are prepared by dimerization of unsaturated fatty acids and can be obtained, for example, under the trade names Radiacid (Oleon) or Pripol (Croda). The use of such dimer fatty acids for the preparation of polyester diols is preferred in the context of the present invention. Preferably used polyols for the preparation of prepolymers (Z.1 .1) are thus polyester diols which have been prepared using dimer fatty acids. Particular preference is given to polyester diols, in the preparation of which at least 50% by weight, preferably 55 to 75% by weight, of the dicarboxylic acids used are dimer fatty acids. Examples of corresponding polyols for the preparation of polyester polyols, preferably polyester diols, are ethylene glycol, 1, 2 or 1, 3-propanediol, 1, 2, 1, 3 or 1, 4 Butanediol, 1, 2, 1, 3, 1, 4- or 1, 5-pentanediol, 1, 2, 1, 3, 1, 4, 1, 5 or 1, 6-hexanediol, hydroxypivalates , Neopentyl glycol, diethylene glycol, 1, 2-, 1, 3- or 1, 4-cyclohexanediol, 1, 2-, 1, 3- or 1, 4-cyclohexanedimethanol and trimethylpentanediol. Preference is therefore given to using diols. Such polyols or diols can of course also be used directly for the preparation of the prepolymer (Z.1 .1), that is to say reacted directly with polyisocyanates.

It is also possible to use polyamines, such as diamines and / or amino alcohols, for the preparation of the prepolymers (Z.1 .1). Examples which may be mentioned as diamines hydrazine, alkyl or Cycloalkyldiamine such as propylene diamine and 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane and as amino alcohols ethanolamine or diethanolamine. The prepolymers (Z.1 .1) contain anionic and / or anionic groups convertible groups. For the introduction of the groups mentioned, starting compounds can be used in the preparation of the prepolymers (Z.1 .1) which, in addition to groups to be reacted in the preparation of urethane bonds, preferably hydroxyl groups, also contain the abovementioned groups, for example carboxylic acid groups. In this way, the corresponding groups are introduced into the prepolymer.

Suitable compounds for introducing the preferred carboxylic acid groups, if containing carboxyl groups, are polyether polyols and / or polyester polyols. In any case, preference is given to using low molecular weight compounds which have at least one carboxylic acid group and at least one isocyanate-reactive functional group, preferably hydroxyl groups. In the context of the present invention, the expression "low molecular weight compound" is to be understood as meaning, in contrast to relatively high molecular weight compounds, in particular polymers, those to which a discrete molecular weight can be assigned as preferably monomeric compounds, ie a low molecular weight compound is in particular no polymer, since the latter always represent a mixture of molecules and must be described by means of average molecular weights, preferably the term low molecular weight compound to understand that the corresponding compounds have a molecular weight of less than 300 g / mol. Preferably, the range is from 100 to 200 g / mol.

Preferred compounds in this sense are, for example, monocarboxylic acids containing two hydroxyl groups, for example dihydroxypropionic acid, dihydroxysuccinic acid and dihydroxybenzoic acid. Especially preferred are alpha, alpha dimethylolalkanoic acids such as 2,2-dimethylolacetic acid, 2,2-dimethylolpropionic acid, 2,2-dimethylolbutyric acid and 2,2-dimethylolpentanoic acid, in particular 2,2-dimethylolpropionic acid. The prepolymers (Z.1 .1) are therefore preferably carboxy-functional. They have, based on the solids, preferably an acid number of 10 to 35 mg KOH / g, in particular 15 to 23 mg KOH / g.

The number-average molecular weight of the prepolymers can vary widely and is for example in the range from 2000 to 20 000 g / mol, preferably from 3500 to 6000 g / mol (measuring method see example part).

The prepolymer (Z.1 .1) is isocyanate group-containing. It preferably has, based on the solids, an isocyanate content of 0.5 to 6.0 wt .-%, preferably 1, 0 to 5.0 wt .-%, particularly preferably 1, 5 to 4.0 wt .-% (Measurement method it sample part).

Since the prepolymer (Z.1.1) is isocyanate group-containing, the hydroxyl value of the prepolymer will, as a rule, be very low. The hydroxyl number of the prepolymer, based on the solids, is preferably less than 15 mg KOH / g, in particular less than 10 mg KOH / g, more preferably less than 5 mg KOH / g (measuring method see example).

The preparation of the prepolymers (Z.1 .1) can be carried out by known and established methods in bulk or solution, more preferably by reacting the starting compounds in organic solvents, such as preferably methyl ethyl ketone at temperatures of for example 60 to 120 ° C, and optionally with use from Catalysts typical for polyurethane production. Such catalysts are known to the person skilled in the art, an example being dibutyltin laurate. It is of course to proceed so that the ratio of the starting components is selected so that the product, that is, the prepolymer (Z.1 .1) contains isocyanate groups. It is also immediately apparent that the solvents should be selected so that they do not undergo any undesired reactions with the functional groups of the starting compounds, ie are inert to these groups insofar as they do not hinder the reaction of these functional groups. The preparation is preferably already carried out in an organic solvent (Z.2) as described below, since this must be present in any case in the composition (Z) to be prepared in stage (I) of the process.

As already stated above, the groups which can be converted into anionic groups in the prepolymer (Z.1 .1) can also be present proportionally as corresponding anionic groups, for example by the use of a neutralizing agent. In this way, the water-dispersibility of the prepolymers (Z.1 .1) and thus also of the intermediate (Z.1) can be adjusted.

Suitable neutralizing agents are, in particular, the known basic neutralizing agents, such as, for example, carbonates, bicarbonates or hydroxides of alkali metals and alkaline earth metals, for example LiOH, NaOH, KOH or Ca (OH) 2. Likewise suitable for neutralization and preferably used in the context of the present invention are organic, nitrogen-containing bases such as amines such as ammonia, trimethylamine, triethylamine, tributylamines, dimethylaniline, triphenylamine, dimethylethanolamine, methyldiethanolamine or triethanolamine and mixtures thereof.

The neutralization of the prepolymer (Z.1 .1) with the neutralizing agents, in particular with the nitrogen-containing, organic bases, after preparation of the prepolymer in the organic phase, that is in solution with an organic solvent, in particular a solvent as described below (Z .2). Of course, the neutralizing agent can already during or before Are added at the beginning of the actual polymerization, then beisp the carboxylic acid group-containing starting compounds are neutralized.

If it is desired to neutralize the groups convertible into anionic groups, in particular the carboxylic acid groups, the neutralizing agent may be added, for example, in such an amount that a proportion of 35 to 65% of the groups is neutralized (degree of neutralization). A range of 40 to 60% is preferred (calculation method see example part).

It is preferred that the prepolymer (Z.1 .1) after its preparation and before its use for the preparation of the intermediate (Z.1) is neutralized as described.

The preparation of the intermediate (Z.1) described here comprises the reaction of the described prepolymer (Z.1 .1) with at least one, preferably exactly one polyamine (Z.1.2a) derived from a polyamine (Z.1.2) ,

The polyamine (Z.1.2a) contains two masked primary amino groups and one or two free secondary amino groups.

As is known, masked amino groups are to be understood as those in which the hydrogen radicals, which are present in free amino groups, are substituted on the nitrogen by reversible reaction with a masking agent. Due to the masking, the amino groups can not be reacted as free amino groups via condensation or addition reactions, so are not reactive in this regard and thus differ from free amino groups. Only the removal again of the reversibly attached masking agent, which in turn gives rise to the free amino groups, then evidently allows the known per se reactions of the amino groups. The principle thus resembles the principle of blocked or masked isocyanates likewise known in the field of polymer chemistry. The primary amino groups of the polyamine (Z.1.2a) can be masked with the masking agents known per se, for example with ketones and / or aldehydes. With such a masking, ketimines and / or aldemines, which do not contain any nitrogen-hydrogen bonds, are then formed with liberation of water, so that no typical condensation or addition reactions of an amino group with another functional group, such as an isocyanate group, can take place.

Reaction conditions for preparing such a masked primary amine, for example a ketimine, are known. Thus, for example, with the addition of heat to a mixture of a primary amine with an excess of a ketone, which simultaneously acts as a solvent for the amine, a corresponding masking can be realized. Preferably, the resulting water of reaction is removed during the reaction to prevent the otherwise possible reverse reaction (unmasking) of the reversible masking. Also, the reaction conditions for unmasking masked primary amino groups are known per se. Thus, for example, the conversion of a masked amine into the aqueous phase is sufficient to shift the equilibrium back to the side of the unmasking by the then existing concentration pressure of the water, thereby producing primary amino groups free of water and a free ketone.

From the above it follows that in the context of the present invention a distinction is made between masked and free amino groups. However, if an amino group is neither specified as masked nor free, this is to be understood as a free amino group.

Preferred masking agents for masking the primary amino groups of the polyamine (Z.1.2a) are ketones. Among the ketones, particularly preferred are those which are an organic solvent (Z.2) as described below. For these solvents (Z.2) must be present anyway in the composition (Z) to be prepared in step (I) of the process. Already stated above, that the production of corresponding with a ketone masked primary amines succeed particularly well in an excess of the ketone. The use of ketones (Z.2) for masking therefore makes it possible to use the correspondingly preferred production process of masked amines without the possibly undesired masking agent having to be removed in a complicated manner. Instead, the masked amine solution can be used directly to prepare the intermediate (Z.1). Preferred masking agents are acetone, methyl ethyl ketone, methyl isobutyl ketone, diisopropyl ketone, cyclopentanone or cyclohexanone, particularly preferably the ketones (Z.2) are methyl ethyl ketone and methyl isobutyl ketone. The preferred masking with ketones and / or aldehydes, in particular ketones, and the resulting production of ketimines and / or aldimines also has the advantage that selectively primary amino groups are masked. Existing secondary amino groups apparently can not be masked and thus remain free. Therefore, a polyamine (Z.1.2a), which also contains one or two free secondary amino groups in addition to the two masked primary amino groups, easily via the said preferred masking reactions of a polyamine (Z.1 .2), which free secondary and primary Contains amino groups can be prepared.

The polyamines (Z.1.2a) can be prepared by masking the primary amino groups of polyamines (Z.1.2) containing two primary amino groups and one or two secondary amino groups. In question, finally, all known aliphatic, aromatic or araliphatic (mixed aliphatic-aromatic) polyamines (Z.1 .2) having two primary amino groups and one or two secondary amino groups. This means that, in addition to the amino groups mentioned, any desired aliphatic, aromatic or araliphatic groups can be present. For example, monovalent groups arranged as terminal groups on a secondary amino group or divalent groups arranged between two amino groups are possible. For the purposes of the present invention, aliphatic is understood as meaning all organic groups which are not aromatic. For example, it may be in addition to the groups mentioned above are aliphatic hydrocarbon groups, that is groups which consist exclusively of carbon and hydrogen and are not aromatic. These aliphatic hydrocarbon groups may be linear, branched or cyclic, which may be saturated or unsaturated. Of course, these groups may also contain both cyclic and linear or branched portions. It is also possible that aliphatic groups contain heteroatoms, in particular in the form of bridging groups such as ether, ester, amide and / or urethane groups. Possible aromatic groups are also known and require no further explanation. It is preferred that the polyamines (Z.1 .2a) have two masked primary amino groups and one or two free secondary amino groups and they have as primary amino groups exclusively masked primary amino groups and as secondary amino groups exclusively free secondary amino groups. Preferably, the polyamines (Z.1.2a) have a total of three or four amino groups, these being selected from the group of the masked primary amino groups and the free secondary amino groups.

Very particularly preferred polyamines (Z.1.2a) are those which consist of two masked primary amino groups, one or two free secondary amino groups and aliphatic-saturated hydrocarbon groups.

Analogous preferred embodiments apply to the polyamines (Z.1 .2), in which then instead of masked primary amino groups free primary amino groups are present.

Examples of preferred polyamines (Z.1.2) from which polyamines (Z.1.2a) can also be prepared by masking the primary amino groups are diethylenetriamine, 3- (2-aminoethyl) aminopropylamine, dipropylenetriamine and N1- (2 (4- (2-aminoethyl) piperazin-1-yl) ethyl) ethane-1,2-diamine (one secondary amino group, two primary amino groups to be blocked) and triethylenetetramine and N, N'-bis (3-amino) aminopropyl) ethylenediamine (two secondary amino groups, two primary amino groups to be blocked).

It is clear to the person skilled in the art that, for purely synthesis-technical reasons, it is not always possible for a theoretically idealized quantitative conversion to take place in the masking of primary amino groups. If, for example, a specific amount of a polyamine is masked, a proportion of 95 mol% or more of the primary amino groups can be masked during masking (determinable by IR spectroscopy, cf. Example). For example, if a polyamine in the unmasked state has two free primary amino groups and the primary amino groups of a given amount of this amine are then masked, it is stated in the present invention that this amine has two masked primary amino groups when greater than 95% mol% of the primary amino groups present in the amount used are masked. On the one hand, this is due to the already mentioned fact that synthesis technology can not always achieve a quantitative turnover. On the other hand, the fact that more than 95 mol% of the primary amino groups are masked means that the largest proportion of the total amount of amines used for masking actually contains exclusively masked primary amino groups, namely exactly two masked primary amino groups.

The preparation of the intermediate (Z.1) comprises the reaction of the prepolymer (Z.1.1) with the polyamine (Z.1.2a) by addition reaction of isocyanate groups (Z.1.1) with free secondary amino groups (Z. .1 .2a). This reaction, which is known per se, then leads to the binding of the polyamine (Z.1 .2a) to the prepolymer (Z.1 .1) to form urea bonds, whereby ultimately the intermediate (Z.1) is formed. It goes without saying that in the preparation of the intermediate (Z.1) preferably no other amines with free or masked secondary or free or masked primary amino groups are used. The preparation of the intermediate (Z.1) can be carried out by known and established methods in bulk or solution, in particular preferably by reaction of (Z.1 .1) with (Z.1.2a) in organic solvents. It is immediately apparent that the solvents should be selected such that they do not undergo any undesired reactions with the functional groups of the starting compounds, ie that they are inert or largely inert towards these groups. The solvent used in the preparation is preferably at least partly an organic solvent (Z.2), in particular methyl ethyl ketone, as described below, since this must be present in any case in the composition (Z) to be prepared in step (I) of the process. In this case, a solution of a prepolymer (Z.1 .1) in a solvent (Z.2) is preferably mixed with a solution of a polyamine (Z.1 .2a) in a solvent (Z.2), the reaction described taking place can.

Of course, the intermediate (Z.1) prepared in this way can be neutralized during or after the preparation with neutralizing agents already described above in the manner also described above for the prepolymer (Z.1 .1). However, it is preferred that the prepolymer (Z.1 .1) is already neutralized in the manner described above prior to its use for the preparation of the intermediate (Z.1), so that neutralization during or after the preparation of (Z.1) is not is more relevant. In such a case, the degree of neutralization of the prepolymer (Z.1 .1) must be equated with the degree of neutralization of the intermediate (Z.1). If no further addition of neutralizing agents is carried out in the course of the process, the degree of neutralization of the polymers present in the finally prepared inventive dispersions (PD) must be equated with the degree of neutralization of the prepolymer (Z.1 .1).

The intermediate (Z.1) has masked primary amino groups. This is evidently achieved by reacting the prepolymer (Z.1.1) and the polyamine (Z.1.2a) to react the free secondary amino groups, but not to react the masked primary amino groups. As already described above, masking ensures that no typical condensation or addition reactions with other functional groups such as isocyanate groups can take place. Of course, this means that the conditions in the reaction are to be chosen so that the masked amino groups remain masked, thereby providing an intermediate (Z.1). Appropriate The expert knows how to adjust conditions and is realized, for example, by the already preferred reaction in organic solvents.

The intermediate (Z.1) is isocyanate group-containing. Accordingly, in the reaction of (Z.1 .1) and (Z.1.2a), the ratio of these components must, of course, be chosen so that the product, ie the intermediate (Z.1), contains isocyanate groups.

Since, as described above, in the reaction of (Z.1.1) with (Z.1.2a) free secondary amino groups are reacted with isocyanate groups, but the primary amino groups are not reacted due to the masking, it is immediately immediately clear that this reaction, the molar ratio of isocyanate groups of (Z.1 .1) to free secondary amino groups of (Z.1 .2a) must be greater than 1. This feature implicitly, nevertheless, clearly and directly results from the feature essential to the invention that the intermediate (Z.1) contains isocyanate groups. However, it is preferred that in the reaction there is an excess of isocyanate groups as defined below. The molar amounts of isocyanate groups, free secondary amino groups and masked primary amino groups in this preferred embodiment satisfy the following condition: [n (isocyanate groups of (Z.1.1)) -n (free secondary amino groups of (Z.1. 2a))] / n (masked primary amino groups of (Z.1.2a)) = 1, 2/1 to 4/1, preferably 1, 5/1 to 3/1, very particularly preferably 1, 8/1 to 2.2 / 1, more preferably 2/1.

In these preferred embodiments, the intermediate (Z.1) formed by reacting isocyanate groups of (Z.1.1) with the free secondary amino groups of (Z.1.2a) has an excess relative to the masked primary amino groups of isocyanate groups. This is ultimately achieved by selecting the molar ratio of isocyanate groups of (Z.1.1) to the total amount of free secondary amino groups and masked primary amino groups of (Z.1.2a) to be such that even after the preparation of (Z.1) and the corresponding consumption of isocyanate groups by the reaction with the free secondary amino groups remains a corresponding excess of the isocyanate groups. For example, if the polyamine (Z.1.2a) has a free secondary amino group and two masked primary amino groups, the molar ratio between the isocyanate groups of (Z.1.1) to the polyamine (Z.1.2a) in the whole particularly preferred embodiment set with 5/1. The consumption of an isocyanate group in the reaction with the free secondary amino group would then mean that for the above-mentioned condition 4/2 (or 2/1) is realized.

The proportion of the intermediate (Z.1) is from 15 to 65 wt .-%, preferably from 25 to 60 wt .-%, more preferably from 30 to 55 wt .-%, particularly preferably from 35 to 52.5 wt. -% and in a very particular embodiment from 40 to 50 wt .-%, each based on the total amount of the composition (Z).

The determination of the proportion of an intermediate (Z.1) can be carried out as follows: The solid of a mixture which contains only organic solvents in addition to the intermediate (Z.1) is determined (measurement method for determination of the solid (also solids content or solids content) called) see example). The solid then corresponds to the amount of the intermediate (Z.1). By taking into account the solids of the mixture, the proportion of the intermediate (Z.1) in the composition (Z) can thus be determined or determined. Since the intermediate (Z.1) is preferably already produced in an organic solvent, that is to say it is anyway present in a mixture after preparation, which contains only organic solvents in addition to the intermediate, this is the method of choice.

The composition (Z) also contains at least one special organic solvent (Z.2).

The solvents (Z.2) have a solubility in water of not more than 38% by weight at a temperature of 20 ° C. (measuring method see example part). Preferably, the solubility in water at a temperature of 20 ° C is less than 30 wt .-%. A preferred range is from 1 to 30% by weight. Accordingly, the solvent (Z.2) has a rather moderate solubility in water, in particular is not completely miscible with water or has no unlimited solubility in water. Fully miscible with water is a solvent when it can be mixed in any proportions with water, without causing a segregation, that is two-phase formation.

Examples of solvents (Z.2) are methyl ethyl ketone, methyl isobutyl ketone, diisobutyl ketone, diethyl ether, dibutyl ether, dipropylene glycol dimethyl ether, ethylene glycol diethyl ether, toluene, methyl acetate, ethyl acetate, butyl acetate, propylene carbonate, cyclohexanone or mixtures of these solvents. Preference is given to methyl ethyl ketone, which at 20 ° C has a solubility in water of 24 wt .-%.

No solvents (Z.2) are thus solvents such as acetone, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, tetrahydrofuran, dioxane, N-formylmorpholine, dimethylformamide or dimethylsulfoxide.

The selection of the special solvents (Z.2) with only limited solubility in water achieves, in particular, that a homogeneous solution can not be formed directly in the aqueous phase in the dispersion of the composition (Z) in step (II) of the process. It is believed that the present dispersion allows the crosslinking reactions (addition reactions of free primary amino groups and isocyanate groups to form urea linkages) proceeding under step (II) to proceed in limited volumes, ultimately allowing the formation of the microparticles as defined above. Preferred solvents (Z.2) in addition to the described water solubility have a boiling point of at most 120 ° C, more preferably of at most 90 ° C (at atmospheric pressure, that is 1, 013 bar). This has advantages in the below-described step (III) of the process, that is to say the at least partial removal of the at least one organic solvent (Z.2) from the dispersion which is prepared in step (II) of the process. Evidently, when using the solvent (Z.2) preferred in this sense, these solvents can be removed, for example, by distillation be removed without the simultaneous significant amounts of the introduced in step (II) of the process water. Thus, for example, eliminates the costly yielding of water to obtain the aqueous character of the dispersion (PD).

The proportion of the at least one organic solvent (Z.2) is from 35 to 85 wt .-%, preferably from 40 to 75 wt .-%, more preferably from 45 to 70 wt .-%, particularly preferably from 47.5 to 65 wt .-% and in a very particular embodiment of 50 to 60 wt .-%, each based on the total amount of the composition (Z). In the context of the present invention, it has been found that by the specific combination of a proportion of the intermediate (Z.1) as specified above in the composition (Z) and the selection of the specific solvents (Z.2) according to the steps described below (II) and (III) can be provided polyurethane-polyurea dispersions containing polyurethane-polyurea particles with the required particle size, which also have the required gel content.

The described components (Z.1) and (Z.2) in total preferably make up at least 90% by weight of the composition (Z). The two components preferably make up at least 95% by weight, in particular at least 97.5% by weight, of the composition (Z). Most preferably, the composition (Z) consists of these two components. In this context, it should be noted that in the case of using neutralizing agents as described above, these neutralizing agents are included in the calculation of the amount of an intermediate (Z.1) the intermediate. In this case, the intermediate (Z.1) in any case has anionic groups, which go back to the use of the neutralizing agent. The cation present after the formation of these anionic groups is therefore likewise attributed to the intermediate. If the composition (Z) contains other components in addition to the components (Z.1) and (Z.2), these are preferably only organic Solvents. Preferably, the solid of the composition (Z) thus corresponds to the proportion of the intermediate (Z.1) in the composition (Z). The composition (Z) thus preferably has a solids content of 15 to 65 wt .-%, preferably from 25 to 60 wt .-%, more preferably from 30 to 55 wt .-%, particularly preferably from 35 to 52.5 wt. % and in a very particular embodiment from 40 to 50% by weight.

A particularly preferred composition (Z) thus contains in total at least 90% by weight of the components (Z.1) and (Z.2) and contains, in addition to the intermediate (Z.1), exclusively organic solvents.

An advantage of the composition (Z) is that it can be prepared without the use of environmentally and harmful organic solvents such as N-methyl-2-pyrrolidone, dimethylformamide, dioxane, tetrahydrofuran and N-ethyl-2-pyrrolidone. Accordingly, the composition (Z) preferably contains less than 10 wt .-%, preferably less than 5 wt .-%, more preferably less than 2.5 wt .-% of organic solvents selected from the group consisting of N-methyl-2 - pyrrolidone, dimethylformamide, dioxane, tetrahydrofuran and N-ethyl-2-pyrrolidone. Preferably, the composition (Z) is completely free of these organic solvents.

In a second step (II) of the process described here, the composition (Z) is dispersed in aqueous phase.

It is known, and also from what has already been said above, that a demasking of the masked primary amino groups of the intermediate (Z.1) is thus realized in step (II). Because the conversion of a masked amine into the aqueous phase releases the reversibly attached masking agent while consuming water, and free primary amino groups are formed. It is also clear that the resulting free primary amino groups then also present with isocyanate groups of the intermediate (Z.1) or the unmasked from the intermediate (Z.1) unmasked intermediate by addition reaction to form urea bonds are reacted.

It is also known that the conversion into the aqueous phase means that in principle there is the possibility that isocyanate groups of the intermediate (Z.1) or of the intermediately (Z.1) formed unmasked intermediate with the water with elimination of carbon dioxide to free Reacting primary amino groups, which in turn can be reacted with remaining isocyanate groups. The above reactions and reactions are of course parallel to each other. Ultimately, a dispersion comprising polyurethane-polyurea particles having a defined average particle size and a defined degree of crosslinking or gel fraction is formed by, for example, intermolecular and intramolecular conversion or crosslinking.

In step (II) of the process described here, the composition (Z) is dispersed in water, wherein a unmasking of the masked primary amino groups of the intermediate (Z.1) and a reaction of the resulting free primary amino groups with the isocyanate groups of the intermediate (Z. 1) and the isocyanate groups of the demasked intermediate formed from the intermediate (Z.1) by addition reaction.

Step (II) of the process described here, that is, the dispersion in the aqueous phase, can be carried out in any desired manner. This means that ultimately it is only important that the composition (Z) is mixed with water or an aqueous phase. Preferably, the composition (Z), which may be present after preparation, for example, at room temperature, that is 20 to 25 ° C, or at room temperature increased temperature, for example, 30 to 60 ° C, are stirred into water, whereby a dispersion is formed. The water introduced, for example, has room temperature. It can be dispersed in pure water (deionized water), that is, the aqueous phase consists only of water, which is preferred. Of course, in addition to water, the aqueous phase may also contain proportionate typical auxiliaries, such as typical emulsifiers and protective colloids. A list of suitable emulsifiers and protective colloids can be found for example in Houben Weyl, Methods of Organic Chemistry, Volume XIV / 1 Macromolecular substances, Georg Thieme Verlag, Stuttgart 1961, S 41 1 ff.

It is advantageous if in step (II) of the process, that is, in the dispersion of the composition (Z) in the aqueous phase, the weight ratio of organic solvents and water is chosen so that the resulting dispersion has a weight ratio of water to organic solvents greater than 1, preferably from 1.05 to 2/1, particularly preferably from 1.1 to 1.5 / 1.

In step (III) of the process described here, the at least partial removal of the at least one organic solvent (Z.2) takes place from the dispersion obtained in step (II). Of course, in step (III) of the process, other solvents, which were present, for example, optionally in the composition (Z), are removed.

The removal of the at least one organic solvent (Z.2) and optionally further organic solvents can be carried out in any known manner, for example by vacuum distillation at temperatures slightly elevated from room temperature, for example 30 to 60 ° C.

The polyurethane-polyurea dispersion (PD) obtained is aqueous (for the basic definition of "aqueous", see above).

A particular advantage of the dispersion (PD) to be used according to the invention is that it can be formulated with only very small proportions of organic solvents, but nevertheless makes possible the inventive advantages described above. The dispersion (PD) to be used according to the invention preferably contains at most 15.0% by weight, particularly preferably at most 10% by weight, very particularly preferably at most 5% by weight and more preferably at most 2.5% by weight of organic solvents (measuring method see example part).

The proportion of the polyurethane-polyurea polymer in the dispersion (PD) is preferably 25 to 55 wt .-%, preferably 30 to 50 wt .-%, more preferably 35 to 45 wt .-%, each based on the total amount of the dispersion (Determination analogous to the determination of the solids content described above for the intermediate (Z.1)).

The proportion of water in the dispersion (PD) is preferably 45 to 75 wt .-%, preferably 50 to 70 wt .-%, more preferably 55 to 65 wt .-%, each based on the total amount of the dispersion.

It is a particular advantage of the dispersion (PD) to be used according to the invention that it can be formulated such that it contains at least 85% by weight, preferably at least 90.0% by weight, very particularly preferably at least 95% by weight. and more preferably at least 97.5% by weight of the polyurethane-polyurea particles and water (the associated value being obtained by summation of the amount of the particles (that is the polymer, determined by the solids content) and the amount of water) , It has been shown that the dispersions are in each case very stable, in particular storage-stable, despite this small proportion of other components, in particular organic solvents. In this way, two relevant advantages are combined. On the one hand, dispersions are provided which can be used in aqueous basecoats and lead there to the performance and technical advantages described in the introduction and also in the examples below. Secondly, adequate freedom of formulation is achieved in the production of aqueous basecoats. This means that in the basecoats additional amounts of organic solvents can be used, which are necessary, for example, to properly formulate various components. In this case, however, the fundamentally aqueous character of the basecoat is not endangered. On the contrary, the basecoats can nevertheless be formulated with comparatively low proportions of organic solvents, ie have a particularly good ecological profile. It is even more preferred that in addition to the polymer, the dispersion contains only water and optionally organic solvents, for example in the form of residual constituents which have not been completely removed in stage (III) of the process. Accordingly, the solids content of the dispersion (PD) is preferably 25 to 55%, preferably 30 to 50%, more preferably 35 to 45%, and more preferably corresponds to the proportion of the polymer in the dispersion.

An advantage of the dispersion (PD) is that it can be prepared without the use of environmental and harmful organic solvents such as N-methyl-2-pyrrolidone, dimethylformamide, dioxane, tetrahydrofuran and N-ethyl-2-pyrrolidone. Accordingly, the dispersion (PD) preferably contains less than 7.5 wt .-%, preferably less than 5 wt .-%, more preferably less than 2.5 wt .-% of organic solvents selected from the group consisting of N-methyl -2- pyrrolidone, dimethylformamide, dioxane, tetrahydrofuran and N-ethyl-2-pyrrolidone. Preferably, the dispersion (PD) is completely free of these organic solvents.

The polyurethane-polyurea polymer present in the dispersion preferably has little or no hydroxyl groups. The OH number of the polymer, based on the solids, is preferably less than 15 mg KOH / g, in particular less than 10 mg KOH / g, more preferably less than 5 mg KOH / g (measuring method see Example).

The proportion of the at least one dispersion (PD), based on the total weight of the aqueous basecoat material (b.1.1), is preferably 5 to 60% by weight, more preferably 15 to 50% by weight and most preferably 20 to 45% by weight. The fraction of the polyurethane-polyurea polymers derived from the dispersions (PD) is preferably from 2.0 to 24.0% by weight, preferably 6.0, based on the total weight of the aqueous basecoat material (b.1.1) to 20.0 wt .-%, particularly preferably 8.0 to 18.0 wt .-%. The determination or definition of the proportion of the polyurethane-polyurea polymers derived from the dispersions according to the invention on Basecoat can be carried out by determining the solids of a dispersion (PD) according to the invention which is to be used in the basecoat.

In the case of a possible specification on basecoats containing preferred dispersions (PD) in a particular range of shares, the following applies. The dispersions (PD) which do not fall into the preferred group may of course continue to be included in the basecoat. The special proportion range then applies only to the preferred group of dispersions (PD). However, it is preferred that for the total proportion of dispersions (PD) consisting of dispersions from the preferred group and dispersions which do not fall into the preferred group, also the specific share range applies.

Thus, if a restriction to a proportion range of 15 to 50% by weight and a preferred group of dispersions (PD) were to be carried out, then this proportion range evidently initially applies only to the preferred group of dispersions (PD). However, it would then be preferred that a total of all originally included dispersions consisting of dispersions from the preferred group and dispersions which do not fall into the preferred group are likewise contained from 15 to 50% by weight. Thus, if 35% by weight of dispersions (PD) of the preferred group are used, then at most 15% by weight of the dispersions of the non-preferred group can be used.

In the context of the present invention, the abovementioned principle applies to all the components of the basecoat material mentioned and their ranges of proportions, for example the pigments mentioned below or also the crosslinking agents mentioned below, such as melamine resins.

The basecoat (b.1 .1) to be used according to the invention preferably contains at least one pigment. By this are to be understood per se known coloring and / or optically effecting pigments. Such color pigments and effect pigments are those skilled in the art, for example, in Römpp Lexikon coatings and printing inks, Georg Thieme Verlag, Stuttgart, New York, 1998, pages 176 and 451 described. The terms coloring pigment and color pigment as well as the terms optically effecting pigment and effect pigment are interchangeable.

Preferred effect pigments are, for example, platelet-shaped metallic effect pigments such as platelet-shaped aluminum pigments, gold bronzes, fire-colored bronzes and / or iron oxide aluminum pigments, pearl pigments such as fish-silver, basic lead carbonate, bismuth oxychloride and / or metal oxide mica pigments and / or other effect pigments such as platelet-shaped graphite, platelet-shaped iron oxide, multilayer Effect pigments of PVD films and / or liquid crystal polymer pigments. Particular preference is given to platelet-shaped metallic effect pigments, in particular platelet-shaped aluminum pigments. Typical color pigments include, in particular, inorganic color pigments, such as white pigments, such as titanium dioxide, zinc white, zinc sulfide or lithopone; Black pigments such as carbon black, iron manganese black or spinel black; Colored pigments such as chromium oxide, chromium oxide hydrate green, cobalt green or ultramarine green, cobalt blue, ultramarine blue or manganese blue, ultramarine violet or cobalt and manganese violet, iron oxide red, cadmium sulfoselenide, molybdate red or ultramarine red; Iron oxide brown, mixed brown, spinel and corundum phases or chrome orange; or iron oxide yellow, nickel titanium yellow, chromium titanium yellow, cadmium sulfide, cadmium zinc sulfide, chrome yellow or bismuth vanadate. The proportion of the pigments is preferably in the range from 1, 0 to 40.0 wt .-%, preferably 2.0 to 35.0 wt .-%, particularly preferably 5.0 to 30.0 wt .-%, each based on the total weight of the aqueous basecoat (b.1 .1).

The aqueous basecoat (b.1 .1) preferably also contains at least one polymer other than the polyurethane-polyurea polymers contained in the dispersions (PD) as binder, in particular at least one polymer selected from among Group consisting of polyurethanes, polyesters, polyacrylates and / or copolymers of said polymers, in particular polyesters and / or polyurethane polyacrylates. Preferred polyesters are described, for example, in DE 4009858 A1 in column 6, line 53 to column 7, line 61 and column 10, line 24 to column 13, line 3 or WO 2014/033135 A2, page 2, line 24 to page 7, line 10 and page 28, line 13 to page 29, line 13 described. Preferred polyurethane-polyacrylate copolymers (acrylated polyurethanes) and their preparation are described, for example, in WO 91/15528 A1, page 3, line 21 to page 20, line 33 and in DE 4437535 A1, page 2, line 27 to page 6, line 22 described. The polymers described as binders are preferably hydroxy-functional and more preferably have an OH number in the range from 15 to 200 mg KOH / g, more preferably from 20 to 150 mg KOH / g. Particularly preferably, the basecoats contain at least one hydroxy-functional polyurethane-polyacrylate copolymer, more preferably at least one hydroxy-functional polyurethane-polyacrylate copolymer and at least one hydroxy-functional polyester.

The proportion of the further polymers as a binder can vary widely and is preferably in the range from 1.0 to 25.0% by weight, preferably 3.0 to 20.0% by weight, particularly preferably 5.0 to 15.0 Wt .-%, in each case based on the total weight of the basecoat (b.1 .1).

In addition, the basecoat (b.1 .1) may contain at least one typical crosslinking agent known per se. If it contains a crosslinking agent, it is preferably at least one blocked polyisocyanate and / or an aminoplast resin, more preferably at least one melamine resin.

If the basecoat (b.1.1) contains crosslinking agents, the proportion of these crosslinking agents is preferably in the range from 0.5 to 20.0% by weight, preferably from 1.0 to 15.0% by weight, particularly preferably 1 , 5 to 10.0 wt .-%, each based on the total weight of the basecoat (b.1 .1). The basecoat (b.1 .1) may also contain at least one thickener. Suitable thickeners are inorganic thickeners from the group of phyllosilicates such as lithium-aluminum-magnesium silicates. It is known, however, that lacquers whose rheological property profile is determined by the main or predominant use of corresponding inorganic thickeners are in need of improvement in terms of their solids content, ie can only be formulated with fairly low solids contents of, for example, less than 20%, without adversely affecting important performance properties become. A particular advantage of the basecoat (b.1 .1) is that it can be formulated without or without a large proportion of such inorganic phyllosilicates used as thickeners. Accordingly, the proportion of inorganic phyllosilicates used as thickener, based on the total weight of the basecoat, is preferably less than 0.7% by weight, more preferably less than 0.3% by weight and even more preferably less than 0.1% by weight. , Most preferably, the basecoat is completely free of such inorganic phyllosilicates used as thickeners.

Instead, the basecoat may contain at least one organic thickener, for example a (meth) acrylic acid (meth) acrylate copolymer thickener or a polyurethane thickener. Preferably used are associative thickeners, such as, for example, the known polyurethane associative thickeners. As associative thickeners, it is known to refer to water-soluble polymers which have strongly hydrophobic groups at the chain ends or in side chains and / or whose hydrophilic chains contain hydrophobic blocks or bundles in the interior. As a result, these polymers have a surfactant character and are capable of forming micelles in the aqueous phase. Similar to the surfactants, the hydrophilic regions remain in the aqueous phase while the hydrophobic regions are incorporated in the particles of polymer dispersions, adsorb on the surface of other solid particles such as pigments and / or fillers, and / or form micelles in the aqueous phase. Ultimately, a thickening effect is achieved without there being an increased settling behavior. Corresponding thickeners are commercially available, for example under the trade name Adekanol (Adeka Corporation). The proportion of organic thickeners is preferably in the range from 0 to 5.0% by weight, preferably 0 to 3.0% by weight, particularly preferably 0 to 2.0% by weight, in each case based on the total weight of the basecoat material , Of very particular advantage of the basecoats used according to the invention (b.1 .1) is that they can be formulated without the use of any thickener, but nevertheless have excellent properties in terms of their rheological profile. In this way, one again achieves a lower complexity of the paint or an increase in the formulation freedom for the basecoat.

In addition, the basecoat (b.1 .1) may contain at least one other additive. Examples of such additives are residue-free or substantially residue-free thermally decomposable salts, of the polymers mentioned as binders various physically, thermally and / or actinic radiation curable polymers as binders, other crosslinking agents, organic solvents, reactive diluents, transparent pigments, fillers, molecular disperse soluble dyes, nanoparticles, light stabilizers, antioxidants, deaerators, emulsifiers, slip additives, polymerization inhibitors, free radical polymerization initiators, primers, leveling agents, film forming aids, sag-control agents (SCAs), flame retardants, corrosion inhibitors, waxes, siccatives, biocides, and matting agents. Such additives are used in the usual and known amounts.

The solids content of the basecoat (b.1.1) may vary according to the requirements of the case. In the first place, the solids content depends on the viscosity required for application, in particular spray application. It is of particular advantage that the basecoat according to the invention can nevertheless have a viscosity at comparatively high solids, which permits adequate application. Preferably, the solids content of the basecoat, if it contains at least one crosslinking agent, is at least 25%, preferably at least 27.5%, more preferably at least 30%.

If the basecoat contains no crosslinking agent, the solids content is preferably at least 15%, preferably at least 18%, more preferably at least 21%.

Under the conditions mentioned, that is to say at the stated solids contents, preferred basecoats (b.1.1) have a viscosity of 40 to 150 mPa · s, in particular 70 to 110 mPa, at 23 ° C. and a shear stress of 1000 l / s -s (see example section for more details on the measuring method). In the context of the present invention, a viscosity in this range at the specified shear stress is referred to as the spray viscosity (processing viscosity). As is known, coating compositions are applied at spray viscosity, that is to say they have a viscosity under the conditions then present (high shear stress) which, in particular, is not too high in order to allow effective application. This means that the adjustment of the spray viscosity is important in order to be able to apply a paint at all by spraying methods and to ensure that a complete, uniform coating film can be formed on the substrate to be coated. It is of particular advantage that a base lacquer (b.1 .1) adjusted to spray viscosity also has a high solids content. The preferred ranges of the solid content, in particular the lower limits, thus show that the basecoat (b.1 .1) in the state capable of application preferably has comparatively high solids contents. The basecoat according to the invention is aqueous (for the definition of "aqueous" see above).

The proportion of water in the basecoat (b.1 .1) is preferably from 35 to 70 wt .-%, more preferably 42 to 63 wt .-%, each based on the total weight of the basecoat. It is again preferred that the percentage sum of the solids of the basecoat and the proportion of water in the basecoat is at least 70% by weight, preferably at least 75% by weight. Preferred among these are ranges of from 75 to 95% by weight, in particular from 80 to 90% by weight. In this specification, the solid, which traditionally has only the unit "%", is given in "% by weight". Since the solids ultimately represent a percentage weight, this form of representation is justified. If, for example, a basecoat has a solids content of 35% and a water content of 50% by weight, the percentage sum of the solids of the basecoat and the proportion of water in the basecoat as defined above is 85% by weight. This means, in particular, that preferred basecoats contain principally polluting components, in particular organic solvents, in relation to the solids of the basecoat, at only small proportions. Preferably, the ratio of the volatile organic content of the basecoat material (in% by weight) and the solids content of the basecoat material (analogous to the illustration above in% by weight) is from 0.05 to 0.7, more preferably from 0.15 to 0.6. In the context of the present invention, the volatile organic content is the proportion of the basecoat which is calculated neither in relation to the proportion of water nor to the solids.

A further advantage of the basecoat (b.1.1) is that it is prepared without the use of environmentally harmful organic solvents such as N-methyl-2-pyrrolidone, dimethylformamide, dioxane, tetrahydrofuran and N-ethyl-2-pyrrolidone can be. Accordingly, the basecoat preferably contains less than 10 wt .-%, preferably less than 5 wt .-%, more preferably less than 2.5 wt .-% of organic solvents selected from the group consisting of N-methyl-2-pyrrolidone, Dimethylformamide, dioxane, tetrahydrofuran and N-ethyl-2-pyrrolidone. Preferably, the basecoat is completely free of these organic solvents.

The preparation of the basecoats can be carried out using the customary and known for the production of basecoats mixing methods and mixing units. For the basecoats (b.1 .2.x) used in the process according to the invention, at least one of these basecoats is the one described for the basecoat (b.1 .1) having features essential to the invention. This means in particular that at least one of the basecoats (b.1 .2.x) contains at least one aqueous polyurethane-polyurea dispersion (PD). The preferred features and embodiments described in the context of the description of the basecoat (b.1 .1) also apply-preferably to at least one of the basecoats (b.1 .2.x).

The inventive method allows the production of multi-layer coatings on plastic substrates, which have excellent adhesion to the plastic substrate.

The present invention also relates to an aqueous mixed lacquer system for the production of aqueous basecoats. The mixed lacquer system comprises, in each case based on the total weight of the aqueous mixed lacquer system,

From 10 to 25% by weight of at least one polyurethane-polyurea polymer derived from at least one dispersion (PD),

0 to 15 wt .-% of a crosslinking agent selected from the group of aminoplast resins,

From 3 to 15% by weight of at least one polyester having an OH number in the range from 15 to 200 mg KOH / g,

From 2 to 10% by weight of at least one polyurethane-polyacrylate copolymer having an OH number in the range from 15 to 200 mg KOH / g,

From 45 to 55% by weight of water, and

From 5 to 15% by weight of at least one organic solvent,

wherein the components described total at least 90 wt .-%, preferably at least 95 wt .-% make up of the mixed paint system. Preferably, the mixed paint system is substantially free of pigments, that is containing less than 1 wt .-% pigments. Most preferably, it is completely free of pigments.

It has been shown that the mixed lacquer system is outstandingly suitable for use by individually tailored completion with, in particular, pigments and, if appropriate, different additives for the production of aqueous basecoats become. One and the same mixing lacquer system can thus be used to prepare various aqueous basecoats by subsequent and individual completion. This of course results in a huge workload and thus increasing the efficiency in the formulation of basecoats, especially on a large scale. The mixed lacquer system can be prepared and stored separately and then completed on an occasion basis with, for example, corresponding pigment pastes.

Accordingly, the present invention also relates to a process for the preparation of aqueous basecoats, which comprises the addition of pigments, in particular in the form of pigment pastes, to a mixed lacquer system as described above.

Examples

Bestimmunqsmethoden

1 . Solids content (solids)

Unless stated otherwise, the solids content, hereinafter also referred to as solid content, according to DIN EN ISO 3251 at 130 ° C; 60 min, weight 1, 0 g, determined. If reference is made in the context of the present invention to an official standard, this naturally includes the version of the standard applicable at the filing date or, if no valid version at this time, the last valid version.

2. Isocyanate content

The determination of the isocyanate content, also referred to below as the NCO content, was achieved by adding an excess of a 2% strength N, N-dibutylamine solution in xylene to a homogeneous solution of the samples in acetone / N-ethylpyrrolidone (1: 1 Vol .-%) determined by potentiometric back-titration of the excess amine with a 0.1 N hydrochloric acid on the basis of DIN EN ISO 3251, DIN EN ISO 1 1909 and DIN EN ISO 14896. About the proportion of a polymer (solid) in solution can be calculated back to the NCO content of the polymer based on solids. 3. Hydroxyl number

The hydroxyl number was based on R.-P. Krüger, R. Gnauck and R. Algeier, Plaste und Kautschuk, 20, 274 (1982), using acetic anhydride in the presence of 4-dimethylaminopyridine as a catalyst in a tetrahydrofuran (THF) / dimethylformamide (DMF) solution at room temperature, the remaining excess of acetic anhydride after acetylation was completely hydrolyzed and the acetic acid was back titrated potentiometrically with alcoholic potassium hydroxide solution. 60 min acetylation times were sufficient in all cases to guarantee complete conversion.

4. acid number

The acid number was determined on the basis of DIN EN ISO 21 14 in a homogeneous solution of tetrahydrofuran (THF) / water (9 parts by volume of THF and 1 part by volume of distilled water) with ethanolic potassium hydroxide solution.

5. degree of neutralization

The degree of neutralization of a component x was calculated from the molar amount of the carboxylic acid groups contained in the component (determined by the acid number) and the molar amount of the neutralizing agent used.

6. Amine equivalent mass

The amine equivalent mass (solution) serves to determine the amine content of a solution and was determined as follows. The sample to be examined was dissolved in glacial acetic acid at room temperature and titrated against 0.1 N perchloric acid in glacial acetic acid in the presence of crystal violet. From the weight of the sample and the consumption of perchloric acid, the amine equivalent mass (solution), the mass of the basic amine solution necessary to neutralize one mole of perchloric acid, was obtained.

7. Masking degree of the primary amino groups

The degree of masking of the primary amino groups was determined by means of IR spectrometry with a Nexus FT-IR spectrometer (Nicolet) with the aid of an IR cuvette (d = 25m, KBr window) at the absorption maximum at 3310 cm ^-1 determined on the basis of concentration series of the amines used and normalization to the absorption maximum at 1 1 66 cm ^-1 (internal standard) at 25 ° C.

8. Solvent content

The content of an organic solvent in a mixture, for example an aqueous dispersion, was determined by gas chromatography (Agilent 7890A, 50m silica capillary column with polyethylene glycol phase or 50m silica capillary column with polydimethylsiloxane phase, carrier gas helium, split injector 250 ° C, oven temperature 40 - 220 ° C, Flammionisationsdetektor, detector temperature 275 ° C, internal standard n-propyl glycol) determined.

9. Number average molecular weight

The number-average molar mass (M _n ) was, unless stated otherwise, by means of a steam pressure osmometer type 10.00 (Knauer) in concentration series in toluene at 50 ° C with benzophenone as a calibration substance to determine the experimental calibration constant of the measuring device according to E. Schröder, G Müller, K.-F. Arndt, "Guide of Polymer Characterization", Akademie- Verlag, Berlin, pp. 47-54, 1982. 10. Mean particle size

The mean particle size (volume average) of the polyurethane-polyurea particles present in the dispersions (PD) according to the invention are determined in the context of the present invention by photon correlation spectroscopy (PCS). Specifically used for measurement was a "Malvern Nano S90" (Malvern Instruments) at 25 ± 1 ° C. The device covers a size range from 3 to 3000 nm and was equipped with a 4mW He-Ne laser at 633 nm. The dispersions (PD) were diluted with particle-free, deionized water as dispersing medium, and then in a 1 ml polystyrene. Measure cuvette with suitable scattering intensity. The evaluation was carried out by means of a digital correlator with the aid of the evaluation software Zetasizer Ver. 6.32 (Malvern Instruments). It was five times and measurements repeated on a second freshly prepared sample. The standard deviation of a 5-fold determination was ^ 4%. The maximum deviation of the arithmetic mean of the volume average (V-average mean) of five individual measurements was ± 15%. The reported mean particle size (volume average) is the arithmetic mean of the mean particle size (volume average) of the individual preparations. The test was carried out using polystyrene standards with certified particle sizes between 50 to 3000 nm.

1 1. gel

The gel content of the polyurethane-polyurea particles (microgel particles) contained in the dispersions (PD) according to the invention is determined gravimetrically in the context of the present invention. Initially, the polymer contained was isolated by freeze-drying from a sample of an aqueous dispersion (PD) (weight 1, 0 g). After determining the solidification temperature, the temperature at which the electrical resistance of the sample no longer changes upon further lowering of the temperature, the main drying of the completely frozen sample was usually carried out in the pressure range of the drying vacuum between 5 mbar and 0.05 mbar, at 10 ° C lower drying temperature than the solidification temperature. By gradually increasing the temperature of the heated shelves to 25 ° C rapid lyophilization of the polymers was achieved, after a drying time of usually 12 hours, the amount of isolated polymer (solid content, determined by the freeze-drying) was constant and even with prolonged freeze-drying not changed anymore. By post-drying at a shelf temperature of 30 ° C and maximum reduced ambient pressure (usually between 0.05 and 0.03 mbar) optimum drying of the polymer was achieved.

Subsequently, the isolated polymer was sintered for one minute at 130 ° C in a convection oven and then extracted for 24 hours at 25 ° C in an excess of tetrahydrofuran (ratio of tetrahydrofuran to solid content = 300: 1). Then, the insoluble portion of the isolated polymer (gel portion) was separated via a suitable frit, dried for 4 hours at 50 ° C in a convection oven, and then weighed back. It was further ensured that at the sintering temperature of 130 ° C and variation of the sintering times between one minute and twenty minutes, the determined gel content of the microgel particles is independent of the sintering time. It is therefore impossible that in the isolation of the polymeric solid downstream crosslinking reactions further increase the gel content.

The gel fraction determined in this way according to the invention is also called the gel fraction (freeze-dried).

At the same time, a proportion of gel, hereinafter also referred to as gel fraction (130 ° C.), was determined gravimetrically by isolating from aqueous dispersion (weight 1, 0 g) a polymer sample at 130 ° C., 60 min (solids). The mass of the polymer was determined to extract the polymer then in analogy to the procedure described above for 24 hours at 25 ° C in an excess of tetrahydrofuran, separate the insoluble fraction (gel fraction), to dry and weigh back. 12. Solubility in water

The solubility of an organic solvent in water was determined at 20 ° C as follows. The respective organic solvent and water were combined in a suitable glass vessel, mixed and the mixture subsequently equilibrated. The amounts of water and the solvent were chosen so that after equilibration two separate phases resulted. After equilibration, a sample of the aqueous phase (that is, the phase containing more water than organic solvent) is withdrawn via a syringe, diluted with tetrahydrofuran in a ratio of 1/10, and the proportion of the solvent is determined by gas chromatography (conditions see item 8) Solvent content).

Unless two phases are formed regardless of the amounts of water and the solvent, the solvent is miscible with water in any weight ratio. This thus infinitely soluble in water solvent (for example, acetone), therefore, in any case, no solvent (Z.2). 13. Volume solids (calculated):

The volume solid was calculated according to VdL-RL 08, "Determination of the Solid Volume of Anti-Corrosive Coating Materials as the Basis for Yield Calculations", Verband der Lackindustrie eV, Edition Dec. 1999. The volume solids VFK (solids volume) was calculated according to the following formula including the material properties of the relevant input materials (density of solvents, density of solids):

VFK = (density (wet paint) x solid content (wet paint)) / density (baked paint)

VFK volume solids in%

Density (wet paint): calculated density of wet paint from the density of the wet paint

Individual components (density solvent

Solids) in g / cm ³

Solid content (wet paint) Solid content (in%) of the wet paint, according to DIN EN ISO

3251 at 130 ° C, 60min, weight 1, 0g determined. Density (baked-on paint) Density of the baked paint on the sheet in g / cm ³

Preparation of a dispersion (PD) A dispersion (PD) was prepared as follows: a) Preparation of a partially neutralized prepolymer solution

In a reaction vessel equipped with stirrer, internal thermometer, reflux condenser and electric heater, 559.7 parts by weight of a linear polyester polyol and 27.2 parts by weight of dimethylolpropionic acid (GEO Specialty Chemicals) were dissolved in 344.5 parts by weight of methyl ethyl ketone under nitrogen. The linear polyester diol was previously from dimerized fatty acid (. Pripol ^® 1012 Croda), isophthalic acid (Fa. BP Chemicals) and hexane-1, 6-diol (Fa. BASF SE) was prepared (weight ratio of the starting materials: dimer fatty acid to isophthalic acid to Hexane-1, 6-diol = 54.00: 30.02: 15.98) and had a hydroxyl value of 73 mg KOH / g solids, an acid number of 3.5 mg KOH / g solids, and a calculated number average molecular weight of 1379 g / mol and a determined by Dampfdrucksmometrie number average molecular weight of 1350 g / mol.

To the resulting solution 213.2 parts by weight of dicyclohexylmethane-4,4'-diisocyanate were added at 30 ° C after the other (Desmodur ^® W, Fa. Bayer Material Science) with an isocyanate content of 32.0 wt .-% and 3.8 parts by weight of dibutyltin dilaurate ( Fa. Merck) added. The mixture was then heated to 80 ° C. with stirring. It was further stirred at this temperature until the isocyanate content of the solution was 1, 49 wt .-% and was constant. Thereafter, 626.2 parts by weight of methyl ethyl ketone were added to the prepolymer and the reaction mixture was cooled to 40 ° C. After reaching 40 ° C 1 1, 8 parts by weight of triethylamine (BASF SE) were added dropwise within two minutes and stirred for a further 5 minutes the approach. b) Reaction of the prepolymer with diethylenetriaminediketimine

Subsequently, 30.2 parts by weight of a 71, 9 wt .-% solution of Diethylentriamindiketimin in methyl isobutyl ketone (ratio of isocyanate groups of prepolymer to Diethylentriamindiketimin (with a secondary amino group): 5: 1 mol / mol, corresponds to two NCO groups per blocked primary amino group ) within a minute, wherein the reaction temperature after addition to the prepolymer solution briefly increased by 1 ° C. The dissolution of diethylenetriaminediketimine in methyl isobutyl ketone was previously prepared by azeotropic removal of water of reaction in the reaction of diethylenetriamine (BASF SE) with methyl isobutyl ketone in methyl isobutyl ketone at 110-104 ° C. Dilution with methyl isobutyl ketone was adjusted to an amine equivalent mass (solution) of 124.0 g / eq. By means of IR spectroscopy, based on the residual absorption at 3310 cm ^-1, a blocking of the primary amino groups of 98.5% was determined. The solids content of the isocyanate group-containing polymer solution was determined to be 45.3%. c) Dispersing and vacuum distillation

After stirring for 30 minutes at 40 ° C, the contents of the reactor were dispersed within 7 minutes in 1206 parts by weight of deionized water (23 ° C). From the resulting dispersion methyl ethyl ketone was distilled off at 45 ° C under vacuum and possibly Solvent and water losses were balanced with deionized water to give a solids content of 40% by weight.

A white, stable, solids-rich, low-viscosity dispersion with crosslinked particles was obtained, which had no settling even after 3 months. The microgel dispersion thus obtained had the following characteristics:

Solids content (1 30 ° C., 60 min, 1 g): 40.2% by weight

Methyl ethyl ketone content (GC): 0.2% by weight

Methyl isobutyl ketone (GC) content: 0.1% by weight

Viscosity (23 ° C, rotational viscometer, shear rate = 1 000 / s): 15 mPa s

Acid number 1 7.1 mg KOH / g

Solids content

Neutralization degree (calculated) 49%

pH (23 ° C) 7.4

Particle size (photocorrelation spectroscopy, volume average) 1 67 nm

Gel content (freeze-dried) 85.1% by weight

Gel content (1 30 ° C) 87.3% by weight

Preparation of Water-Based Lacquers to be Used According to the Invention The components listed in Table 1 were stirred together in the order given to aqueous mixed-mixing systems. While the paint system 1 contains a melamine resin as a crosslinking agent, the paint system 2 is completely free of crosslinking agents. Both mixing systems contain the dispersion (PD) described above and are completely free of thickeners such as inorganic thickeners.

Table 1: Mixing systems 1 and 2

MischlackMischlack¬

component

system 1 system 2

Parts by weight parts by weight

Dispersion (PD) 55,000 54,000 Butyl glycol 5,300 4,500

Water 8,300 1 1, 000

Polyester prepared according to page 28, lines 13

5,400 - to 33 of WO 2014/033135 A2

Polyester dispersion; prepared according to example

- 12,500

D, column 16, lines 37-59 of DE 4009858 A1

Polyurethane-polyacrylate copolymer dispersion prepared according to page 7, line 55 to 9,700 9,000

Page 8, line 23 of DE 4437535 A1

Aqueous solution of dimethylethanolamine (10%

1, 600 3,300

ig)

Polypropylene glycol 1, 400 1, 500

TMDD BG 52 (BASF) (CONTAINS 48% by weight)

3,200 3,000

BUTYL CELLOSOLVE)

Melamine-formaldehyde resin (Resimene 755) 10,100 -

Starting from the mixed-paint systems described in Table 1, different unifarbene aqueous basecoats and colored and effect-based aqueous basecoats were prepared. For this purpose, the mixed-paint systems were completed with the desired tinting pastes and optionally further additives and solvents. Thus, for example, as needed, UV protection additives and / or additives for the course or the reduction of the surface tension can be used.

Tables 2 to 5 show the compositions of the prepared aqueous basecoats, wherein the indicated components were mixed in the order given. In this case, the constituents of the mixed-paint systems are also listed individually, since the use of the mixed-paint systems is advantageous, but not absolutely necessary. The same basecoats result by appropriately combining the individual components in the specified order. All aqueous basecoats (BC) had a pH of 7.8 to 8.6 and a spray viscosity of 70 to 1 10 mPa s at a shear stress of 1000 s ^~ measured with a rotary viscometer (Rheomat RM 180 from Mettler Toledo) at 23 ° C, on. Table 2: basecoats 1 (gray) and 2 (white), based on mixed lacquer system 1

The basecoats 1 and 2 are stable for at least 4 weeks at 40 ° C., ie they show no settling tendency at this time and no significant change (less than 15%) in the low shear viscosity (shear stress of 1 s ^~ measured with a rotary viscometer) on. The basecoat 1 has a solids content of 42% and a calculated volume solids of 35%. The basecoat 2 has a solids content of 47% and a calculated volume solids of 35%.

Table 3: basecoats 3 (gray) and 4 (white), based on mixed lacquer system 2

The basecoats 3 and 4 are stable in storage for at least 4 weeks at 40 ° C, that is they have at this time no tendency to settle and no significant change (less than 15%) of the low shear viscosity (shear stress of 1 s ^~ measured with a rotational viscometer) on. The basecoat 3 has a solids content of 38% and a calculated volume solids content of 32%. The basecoat 4 has a solids content of 42% and a calculated volume solids content of 31%. Table 4: basecoats 5 (silver) and 6 (red), based on mixed lacquer system 1

Component BC 5 (silver) BC 6 (red)

Parts by weight parts by weight

Dispersion (PD) 30,733 30,483

Butylglycol 2.962 2.937

Water 4,638 4,600

Polyester, prepared according to page 28, lines 13

3,017 2,993 to 33 of WO 2014/033135 A2

Polyurethane-polyacrylate mixed polymer dispersion prepared according to page 7, line 55 to 5,421 5,376 page 8, line 23 of DE 4437535 A1

Aqueous solution of dimethylethanolamine (10%

0,894 0,887 ig)

Polypropylene glycol 0,782 0,776

TMDD BG 52 (BASF) (CONTAINS 48% by weight)

1, 788 1, 774 BUTYL GLYCOL)

Melamine-formaldehyde resin (Resimene 755) 5.644 5.598

Toning Paste (Black) - 0,764

Toning paste (red) - 18,442

Aluminum pigment (ALU STAPA IL HYDROLAN

6,348 - 2192 NR.5)

Aluminum pigment (ALU STAPA IL HYDROLAN

2,727 - 2197 NR.5)

Aluminum pigment (PALIOCROM ORANGE

- 0.764 L2804 (ex EH 0)

Butyl glycol 5,722 0,764

Polyester; prepared according to Example D, column

5,722 0,764 16, lines 37-59 of DE 4009858 A1

Aqueous solution of dimethylethanolamine (10%

0.805 0.076 ig)

Micapigment (MEARLIN EXT. FINE RUSSET 459

- 2.246 V)

Micapigment (MEARLIN EXT. SUPER RUSSET

- 0.764 459 Z) Mixture prepared according to column 1 1, lines 1

- 9,365

to 13 of EP 1534792 B1

TINUVIN 384-2, 95% MPA 0.536 0.640

TINUVIN 123 0.358 0.430

BYK-381 - 0.478

Water 21, 314 8,122

Aqueous solution of dimethylethanolamine (10%

0.590 0.956

ig)

The basecoats 5 and 6 are stable in storage for at least 4 weeks at 40 ° C, that is they have at this time no tendency to settle and no significant change (less than 15%) of the low shear viscosity (shear stress of 1 s ^~ measured with a rotational viscometer) on. The basecoat 5 has a solids content of 31% and a calculated volume solids content of 27%. The basecoat 6 has a solids content of 38% and a calculated volume solids content of 34%

Table 5: basecoats 7 (silver) and 8 (red), based on mixed lacquer system 2

Component BC 7 (silver) BC 8 (red)

Parts by weight parts by weight

Dispersion (PD) 31, 355 30.283

Butyl glycol 2,613 2,524

Water 6,387 6,169

Polyester dispersion; prepared according to example

7,258 7,010

D, column 16, lines 37-59 of DE 4009858 A1

Polyurethane-polyacrylate copolymer dispersion prepared according to page 7, lines 55 to 5,226 5,047

Page 8, line 23 of DE 4437535 A1

Aqueous solution of dimethylethanolamine (10%

1, 887 1, 822

ig)

Polypropylene glycol 0.871 0.841

TMDD BG 52 (BASF) (CONTAINS 48% by weight)

1, 742 1, 682

BUTYL CELLOSOLVE) Toning paste (Black) 0,540

Toning paste (Red) 12,800

Aluminum pigment (ALU STAPA IL HYDROLAN

4,666

2192 NR.5)

Aluminum pigment (ALU STAPA IL HYDROLAN

2,000

2197 NR.5)

Aluminum pigment (PALIOCROM ORANGE

0,540

L2804 (ex EH 0)

Micapigment (MEARLIN EXT. FINE RUSSET 459

1, 620

V)

Micapigment (MEARLIN EXT. SUPER RUSSET

0,540

459 Z)

Mixture prepared according to column 1 1, lines 1

13,332 8,100

to 13 of EP 1534792 B1

Butyl glycol 5,000 2,700

Organic thickener (PAc thick., AS S130 sol.) 7,500 5,400

Water 10,000 10,000

Water 4,000 4,000

Aqueous solution of dimethylethanolamine (10%

1, 700 2,000

ig)

The basecoats 7 and 8 are stable for storage for at least 4 weeks at 40 ° C., ie they show no settling tendency at this time and no significant change (less than 15%) in the low shear viscosity (shear stress of 1 s ^~ measured with a rotary viscometer) on. The basecoat 7 has a solids content of 19% and a calculated volume solids content of 22%. The basecoat 8 has a solids content of 24% and a calculated volume solids content of 21%

Preparation of the above-mentioned tinting pastes: The tinting paste (black) was prepared from 25 parts by weight of an acrylated polyurethane dispersion prepared according to International Patent Application WO 91/15528 Binder Dispersion A, 10 parts by weight carbon black, 0.1 part by weight methyl isobutyl ketone, 1, 36 parts by weight dimethylethanolamine (10% pure) Deionized water), 2 parts by weight of one commercially available polyethers (Pluriol® P900 BASF SE) and 61, 45 parts by weight of deionized water.

The tinting paste (white) was prepared from 43 parts by weight of an acrylated polyurethane dispersion prepared according to International Patent Application WO 91/15528 Binder Dispersion A, 50 parts by weight of titanium rutile 231 0, 3 parts by weight of 1-propoxy-2-propanol and 4 parts by weight of deionized water.

The tinting paste (red) was composed of 38.4 parts by weight of an acrylated polyurethane dispersion prepared according to International Patent Application WO 91/15528 Binder Dispersion A, 47.1 parts by weight of Bayferrox® 1 3 BM / P, 0.6 parts by weight of dimethylethanolamine (10% in VE Water), 4.7 parts by weight of a commercially available polyether (Pluriol® P900 from BASF SE), 2 parts by weight of butylglycol and 7.2 parts by weight of deionized water. Preparation of a Waterborne Basecoat V1 to be Used for Comparison

Component BC V1 (Silver)

Parts by weight

3% NaMg layered silicate solution 21, 0

Water 1, 80

Polyurethane-polyacrylate copolymer dispersion prepared according to page 7, lines 55 to 3.50

Page 8, line 23 of DE 4437535 A1

TMDD BG 52 (BASF) (CONTAINS 48% by weight)

0.4

BUTYL CELLOSOLVE)

Water 3,00

Rheovis® PU1250 (BASF) 0.1

Butyl glycol 0.1

Water 3,00

Butyl glycol 4,50

Polyester dispersion; prepared according to example

2.00

D, column 16, lines 37-59 of DE 4009858 A1 TMDD BG 52 (BASF) (CONTAINS 48% by weight 0.30

BUTYL CELLOSOLVE)

Melamine-formaldehyde resin (Luwipal 052) 3.80

Aqueous solution of dimethylethanolamine (10% - 0.20

ig)

Polypropylene glycol 0.90

Water 2,00

Polyurethane-polyacrylate copolymer dispersion prepared according to page 24, line 14 18.00

to page 26, line 6 and page 34, line 26 to

Page 35, line 30 of WO 2015/007427 A1

TMDD BG 52 (BASF) (CONTAINS 48% by weight)

0.50

BUTYL CELLOSOLVE)

Aqueous solution of dimethylethanolamine (10% - 0.50

ig)

Water 3,00

Rheovis® AS S130 (BASF) 0.50

Water 7.50

Butanol 1, 50

Water 2,00

Aluminum pigment (ALU STAPA Hydrolux

0.80

VP51284)

Aluminum pigment (ALU STAPA Hydrolux 2192) 3,50

Butyl glycol 5.20

Polyester dispersion; prepared according to example

2.60

D, column 16, lines 37-59 of DE 4009858 A1

Aqueous solution of dimethylethanolamine (10% - 0.30

ig)

Water 4,50

Triisobutyl phosphate 1, 00

Basecoat V1 is stable in storage for at least 4 weeks at 40 ° C., ie it exhibits no settling tendency at this time and no significant change (less than 15%) in the low-shear viscosity (shear stress of 1 s ^~ measured with a rotation Viscometer). It has a solids content of 19% and a calculated volume solids of 16%.

Production of multicoat paint systems using the basecoats 1 to 8 and V1 and application-oriented examination of these coatings

As plastic substrates for the painting, flame-pretreated Hifax sheets (PP / EPDM blend) were used. Optionally, a cured surfacer coat was then prepared on the fired substrates using a commercial filler (see Table A).

Subsequently, in each case a color and / or effect basecoat was applied by electrostatic spray application in a layer thickness of 20 micrometers, then flashed for 10 minutes at room temperature and then dried at 80 ° C for 10 minutes. A commercially available two-component clearcoat material in a layer thickness of 35-45 micrometers was applied to this intermediately dried basecoat film by electrostatic spray application and the overall structure was then flashed off again for 10 minutes at room temperature and then cured at 80 ° C. for 30 minutes. The adhesion properties of the multicoat paint systems produced in this way were investigated. The cross-cut test in accordance with DIN EN ISO 2409, the stone impact test in accordance with PV3.14.7 in accordance with DIN EN ISO 20567-1, the steam jet test in accordance with PV1503 with adaptation to DIN 55662, if necessary combined with the condensation test (SKK) in accordance with PV3.1 6.1, were carried out DIN EN ISO 6270-2. Low values correspond to good adhesion.

Table A shows the corresponding results Table A: Adhesive properties

The results show that the adhesion properties of the multicoat paint systems according to the invention to plastic substrates are markedly improved in comparison to multicoat paint systems which were produced using the basecoat material V1. In addition, the adhesion properties of the multicoat paint systems according to the invention are outstanding despite the omission of a filler.

Claims

claims

1 . Method for producing a coating (M) on a plastic substrate (S) comprising (1) production (1 .1) of a basecoat film (B.1 .1) or (1 .2) of several directly successive basecoat films (B.1 .2 .x) on the plastic substrate (S) by (1 .1) application of an aqueous basecoat (b.1 .1) to the substrate (S) or (1 .2) application of several basecoats (b.1 .2 (2) producing a clearcoat film (K) directly on (2.1) the basecoat film (B.1.1) or (2.2) an uppermost basecoat film (B.1.2.x) by applying a clearcoat material (k) directly on (2.1) the basecoat film (B.1.1) or (2.2) the topmost basecoat film (B.1.2.x),

2. The method according to claim 1, characterized in that the polyurethane-polyurea particles, each in reacted form,

(Z.1 .1) at least one isocyanate group-containing polyurethane prepolymer containing anionic groups and / or groups which can be converted into anionic groups, and (Z.1.2) at least one polyamine containing two primary amino groups and one or two secondary amino groups, and the dispersion (PD) consists of at least 90 wt .-% of the polyurethane-polyurea particles and water.

3. The method according to claim 1 or 2, characterized in that the anionic and / or convertible into anionic groups carboxylate and / or

Carboxylic groups are.

4. The method according to claim 2 or 3, characterized in that the polyamine (Z.1 .2) consists of one or two secondary amino groups, two primary amino groups and aliphatic-saturated hydrocarbon groups.

5. The method according to any one of claims 1 to 4, characterized in that the polyurethane-polyurea particles contained in the dispersion have an average particle size of 1 10 to 500 nm and a gel content of at least 80%.

6. Method according to claim 1, characterized in that the basecoat (b.1. x) also contains at least one hydroxy-functional polymer as a binder selected from the group consisting of polyurethanes, polyesters, polyacrylates and copolymers of these polymers.

7. The method according to any one of claims 1 to 6, characterized in that the basecoat (b.1 .1) or at least one of the basecoats (b.1 .2.x), preferably all of the basecoats (b.1 .2. x) are one-component coating agents.

8. The method according to any one of claims 1 to 7, characterized in that the common curing (3) is carried out at temperatures between 40 and 100 ° C for a period of 5 to 60 min.

9. The method according to any one of claims 1 to 8, characterized in that the plastic substrate comprises polypropylene / ethylene-propylene-diene copolymer blends (PP / EPDM blends), preferably consists thereof.

10. The method according to any one of claims 1 to 9, characterized in that the basecoat (b.1 .1) and the basecoat materials (b.1 .2.x), if they contain at least one crosslinking agent, a solids content of at least 25%. and, if the basecoat (b.1.1) and the basecoat materials (b.1.2.x) contain no crosslinking agent, have a solids content of at least 15%.

1 1. A method according to claim 10, characterized in that the basecoats at 23 ° C and a shear stress of 1000 1 / s have a viscosity of 40 to 150 mPa-s.

12. The method according to any one of claims 1 to 1 1, characterized in that the basecoat (b.1 .1) or at least one of the basecoats (b.1 .2.x), preferably all of the basecoats (b.1 .2 .x) contains at least one crosslinking agent selected from the group of blocked polyisocyanates and aminoplast resins.

13. The method according to any one of claims 2 to 12, characterized in that the prepolymer (Z.1 .1) contains at least one prepared using diols and dicarboxylic acids polyester diol, wherein in the preparation of the polyester diols at least 50 wt .-%, preferably 55 to 75 wt .-%, of the dicarboxylic acids used are dimer fatty acids.

14. The method according to any one of claims 1 to 13, characterized in that the basecoat (b.1 .1) or the basecoats (b.1 .2.x) are applied by electrostatic spray application or pneumatic spray application.

15. Multi-layer coating (M), which was prepared by the method according to any one of claims 1 to 14.